In a remarkable exchange, House Speaker Paul Ryan (R-WI) was asked during CNN’s Thursday town hall to explain to a cancer patient who said the Affordable Care Act saved his life how congressional Republicans could move forward with repeal of the law without a replacement plan ready.

Jeff Jeans, a lifelong Republican who said he worked on the Reagan and George W. Bush campaigns, said he opposed the ACA until he received a surprise cancer diagnosis at 49. He was given six weeks to live.

“Thanks to the Affordable Care Act, I’m standing here today alive,” he said. “Being both a small business person and someone with pre-existing conditions, I rely on the Affordable Care Act to be able to purchase my own insurance. Why would you repeal the Affordable Care Act without a replacement?”

Ryan said he “wouldn’t do that” and expressed relief that Jeans lived to tell his story.

Jeans interjected to thank President Barack Obama “from the bottom of my heart” for passing the healthcare law.

“I would be dead if it weren’t for him,” Jeans told Ryan.

The House Speaker affirmed that his conference was working on a replacement “right now” that would cover those with pre-existing conditions, like Jeans, without causing the premium increases that have been significant in some states. Ryan voiced support for a return to state-run, high-risk pools, which allow sick people to buy insurance separately with subsidies from states, insurers and the federal government. Health care experts have warned that these pools, which were in place in 35 states for those with preexisting conditions before the ACA passed, had long wait lists and other restrictions for coverage, as well as astronomically high premiums.

Congressional Republicans are moving forward with repeal this week, with the Senate on Thursday passing a budget resolution that smooths the path for Obamacare repeal. The House will vote on the resolution Friday.

Watch a clip of their exchange below via Politico’s Dan Diamond.