When it’s 35 degrees in Tahoe with fresh powder accumulating by the hour, a 4-1/2-year-old boy should be overjoyed.

My son Theo wasn’t. He was miserable.

It was Presidents’ Day weekend. I was with my wife Anne, Theo and his younger brother Hugo in South Lake Tahoe, about 200 miles from our home in the Bay Area. That Sunday while inner tubing on the cottony snow, Theo was cranky, lethargic and complaining of neck pain.

Normally a jovial kid, he’d been a bit sick in recent weeks with an occasional fever, but nothing of notable concern to our pediatrician. Back home two days later, Anne took him to the hospital for an X-ray.

The results were frightening. Theo had a giant mass in his chest that was pushing on his heart and lungs. A CT scan pointed to the nightmare scenario: acute lymphoblastic leukemia (ALL).

It was the hardest night of our lives. Theo was despondent and struggling to breathe on his own. He had to wear a mask that covered his entire face, making it difficult for him to talk. He was sent to the intensive care unit as soon as a bed was ready.

Theo’s lungs were in such a vulnerable state that the medical staff didn’t think he could handle the anesthesia needed for a biopsy. It was a good 72 hours before we started to see improvement.

For 24 days, Theo was confined largely to a hospital bed in Oakland and under the constant care of world-class oncologists, hematologists, radiologists, anesthesiologists and, of course, nurses. Since returning home, he’s had multiple hospital visits a week for blood draws, imaging and chemo treatments, including lumbar punctures.

Theo’s doing great now and is expected to fully recover. For that, we have the tremendous advances in cancer research and our brilliant caregivers to thank.

But just as we’re celebrating the miracle of modern medicine, we’re simultaneously watching a much darker story unfold — our country’s medical system is under assault.

As Theo was busy constructing a Lego fire station over the weekend while in the hospital for chemo, legislators in Washington were furiously working to slash health coverage for kids exactly like him.

The Senate’s measure to overhaul Obamacare, following the narrow passage of a similar bill in the House of Representatives last month, would pull hundreds of billions of dollars out of the healthcare system. Despite describing the House bill as “mean,” President Trump has voiced — or tweeted — his support for the Senate’s plan.

The Congressional Budget Office estimated on Monday that, should it become law, the bill would add 22 million people to the ranks of the uninsured by 2026. Only a handful of the 52 Republican senators have openly opposed the bill, which Senate Majority Leader Mitch McConnell had hoped to bring to a vote this week. That’s now being delayed until after the July 4 recess, NBC confirmed on Tuesday, while the Republicans seek more time to secure the necessary 50 votes.

“Republicans decided to campaign for the past seven years on repeal and replace so they feel compelled to deliver on that promise,” said Gerald Kominski, director of UCLA’s Center for Health Policy Research who’s spent 40 years studying health care policy. This isn’t an actual repeal, but “come hell or high water they’re trying to ram some bill through,” he said.

To be clear, Theo is fully insured. I’m a technology editor at CNBC.com in San Francisco (health care is not my beat) and my employer-sponsored plan is keeping Theo covered and my family out of debt. We reached our annual out-of-pocket maximum on day four in the hospital. And we’re in California, which is among the safest states for the ongoing protection of people with pre-existing conditions.

But there’s something more at stake. Hospitals are poised to suffer badly, punishing society in ways that are hard to understand unless you or your kid has faced a life-threatening illness.

For insight on that topic, I turned to Theo’s principal oncologist, Carla Golden.

On Saturday, as I was helping Theo build his firehouse, Dr. Golden stopped by our room.

She told me that well over half of Children’s Hospital’s patients are on Medicaid. In California, 3.7 million people enrolled in Medi-Cal (the state’s Medicaid program) after the ACA expanded access. The Republican bill seeks to eliminate funds for the expansion plan after 2020.

Children’s, a non-profit hospital in a low-income area, aims to provide the same quality of service to patients regardless of their level of coverage or ability to pay.

“Part of our mission is to take care of everybody who walks through our doors,” Golden said. “We have a lot of people who don’t have good insurance and that puts a bigger burden on the hospital, but our goal is to keep taking care of those patients.”

So what happens if fewer people are covered?

It’s pretty simple — more bills go unpaid. And that’s a massive problem for everybody, including Theo.

We are counting on Dr. Golden and her team of specialists to provide continuing care. We need the hospital to be financially viable so it can continue to lure the best and brightest physicians and researchers committed to saving children’s lives.

It’s not just doctors. Children’s Hospital has a group called child life services, which offers critical emotional support to kids and their families. When Theo was headed into surgery to be placed on a heart and lung machine, we were in no position to prepare him for what was coming. The hospital did that for us, through stories, stuffed animals and lighthearted games.

Music therapists, physical therapists, occupational therapists, and dieticians are also on the payroll. They play essential roles in a kid’s recovery and wellness. The hospital needs money to keep them.

“There are services other than immediate acute medical care that are important for one’s development and for maintaining one’s spirits,” said Henry Aaron, a senior fellow in economic studies at the Brookings Institution and an expert on health policy. “We’re not going see it in any one simple way, but the effect of these changes would be systemic in the health care delivery system.”

Aaron is vice chair of Washington, D.C.’s Health Benefit Exchange Authority, established under the Affordable Care Act. Try finding a doctor who disagrees with him.

The American Medical Association said on Monday that the replacement bill “will expose low and middle-income patients to higher costs and greater difficulty in affording care.” The American Academy of Pediatrics said last week that the measure “fails to meet children’s needs.”

For Dr. Golden, who has spent decades working in cancer research, the attempted health care legislation is just the latest effort to set her industry back.

In mid-March, three weeks after Theo’s diagnosis, President Trump unveiled his proposal to slash funding for the National Institutes of Health by 18 percent. The NIH is the parent of the National Cancer Institute and funds the Children’s Oncology Group, whose research has helped lift survival rates among pediatric cancer patients to 80 percent from almost incurable 50 years ago.

“In my lifetime, kids with cancer didn’t survive,” said Golden, who’s been a member of the Children’s Oncology Group since 1995. “Now they grow up and do everything they want to do. It’s because of research, and the federal government has been a really big part of that.”

Whether it’s research or insurance, Republican legislators are now focused on shrinking government spending in just about every sector but the military.

Even members of their own party are struggling to make sense of it. Craig Garthwaite, co-director of Kellogg’s Health Enterprise Management Program at Northwestern, is a lifelong Republican and was a critic of Obamacare. He sees nothing in the Republican proposal that’s designed to improve the health system.

Rather, he says the party’s effort to curb healthcare funding is fundamentally bad for innovation because it forces people with illnesses or sick dependents, like me, to prioritize health coverage over all else. The Obamacare exchanges were designed in part so that people working for start-ups or freelancing could get reasonable coverage.

The federal subsidies provided by Obamacare for coverage on the exchanges are on the verge of shrinking.

“It’s an asinine way to run an economy,” Garthwaite said. “We want the most productive employer-employee matches we can get.”

Obamacare was never a panacea. It added 20 million Americans to the insurance rolls, but it hasn’t been able to reel in the exploding costs of care. Premiums and co-pays have been going up, making care unaffordable even for some people with coverage.

But instead of trying to fix the ACA, the Republican bill promises to pull billions of dollars a year away from an already stressed system and pass the burden onto states, while handing almost $1 trillion in tax cuts to the wealthiest Americans.

My wife and I have spent countless hours over the past four months roaming the fifth floor of Children’s Hospital, also known as the hematology-oncology department. In the playroom, we’ve mingled with kids of all ages, ethnic backgrounds and socioeconomic groups. They’re all just as bald as Theo and every bit as happy to be painting, singing and playing board games.

They’re here today because of medical breakthroughs funded with federal dollars. They’re also here because of a health care system that, despite its many flaws, has given them a safety net.

It’s no time to roll back the clock.