From his website stallman.org:
Richard Stallman has cancer. Fortunately it is slow-growing and manageable follicular lymphona, so he will probably live many more years nonetheless. But he now has to be even more careful not to catch Covid-19.
Recent video of him speaking at GNU 40 Hacker Meeting. Screenshots of video stream.
He mentioned once that he can use a bank that doesn't use free software because he's not logging in to it to do general purpose computing. I think the same would probably apply to medical treatments.
I believe he does extend it to JavaScript however, so if he were required to run unfree javascript on a webpage relating to his treatment that could be a problem.