Mr. Murphy is among many hospital executives now anxious about the possibility of seeing a bump in uninsured patients if the health law is repealed, while not getting back the federal funds they gave up under the health law. “I do think it would be problematic if part of the deal was changed and not the whole deal,” he said.

Mr. Pence expanded Medicaid only after the Obama administration agreed to let Indiana do it in its own way: Instead of getting virtually free coverage, as Medicaid recipients in many other states do, people enrolled in Indiana’s expansion pay up to 5 percent of their income toward it. Mr. Trump appears interested in promoting Indiana’s “personal responsibility” model: He has picked its chief architect, Seema Verma, to run the Centers for Medicare and Medicaid Services.

Since Mr. Kloski had no income when he enrolled, he paid $1 a month; he has since been classified as “medically frail” and does not have to pay anything.

Medicaid has paid for virtually all of his cancer care, including a one-week hospitalization after the diagnosis, months of chemotherapy, and frequent scans and blood tests.

But Mr. Kloski and his mother, Renee Epperson, are still not fans of the health law over all. They believed that it required that Mr. Kloski be dropped, when he turned 26, from the health plan his mother has through her job at Target — not understanding that it was the law that kept him on the plan until he was 26.

Mr. Kloski paid a penalty for going uninsured in 2014 rather than even explore whether he might qualify for a subsidy and find an affordable private plan through the marketplaces.

“There were so many horror stories about how expensive it was going to be,” Ms. Epperson, 47, recalled. “Justin said, ‘I’m not even going to try it, Mom.’”