What can I do?

Over the weekend, ThumbSucker and I completed watching Sex in the City. In just more than one month, we watched all six seasons of the show on DVD. In the sixth season, Samantha learned that she had breast cancer, and it was almost painful for ThumbSucker to watch.

What's painful to watch is ThumbSucker when he's not feeling or looking well. He's on a handful of meds that supposedly help him, but from what I can see, he is tired and fatigued, yacking, has headaches, and sometimes does not want to get out of bed. But he forces himself to be productive. And I'll force him to keep as busy as possible. But what else should I do? I do not have a clue as to what I should do, and I feel like an asshole because I push him to not slow down as I fear he will not return to some state of normal.

IM CONVO
ThumbSucker: One other thing I didn't tell you that I probably should have.
me: and that is?
ThumbSucker: So my father died of a rare degenerative brain cancer - my biggest fear through all of this has been that this is somewhat related. They don't know if there is any link or not. That's partly why this has been really hard, I saw my dad have a very slow, very painful, very sad illness and death. He wasn't aware for the last six months what was going on etc.
me: but he was much older.
me: so what is the latest? do you have lymphoma, or not?
ThumbSucker: in theory I don't know - chemo has taken care of that, but I still have something wrong with my brain, maybe a small tumor that they can't see. The issue with the brain is that there seems to be limited things they can diagnose while you are still alive. For example, my father's true condition was determined when they did analysis of his brain after he died.
me: and what did they learn? and more importantly, what did you and your family learn?
ThumbSucker: just that it was a rare degenerative cancer but from what I understand from them there is no easy test for it. there is no direct link that the doctors here can make based on what I told them so it may not be related but they don't have access to his medical records.
me: why do they not have access to the records?
ThumbSucker: Different jurisdictions, Irish medical records are sealed.
ThumbSucker: there is some gene-based testing that will be available within the next couple of years that can tell if you have the gene that makes you a higher risk for having it.
me: so what is your doc's recommendation?
ThumbSucker: continue to evaluate blood tests and take MRIs to see if any other indications develop as well as additional testing that will be available in the future
ThumbSucker: as well as continue on certain drugs to reduce risk of strokes or seizures.
ThumbSucker: I guess the kind of headaches I get put me at higher risk for early stroke.
me: ugh. goodness.
ThumbSucker: anyway, sorry to unload this all on you but I thought I should tell you this also.
me: thanks. it's late, but thanks.
ThumbSucker: to be honest, in all of this my fear isn't of dying. my fear is that I would end up like my father not knowing for months what was going on and having no control.
me: but that would be years from now. And when you're in, then you're in it... and you do not have control.
ThumbSucker: the sad thing though is you have some lucid periods. I think there were days when my dad would have some idea because he would cry.
me: ugh. sad.
me: what would you want to do at that period? again, keep in mind that you're years away from this.
ThumbSucker: if I knew I would get it I would want out on my own terms - that whole decline is too much to put yourself through as well as those around you.
me: i'm the same way. i'd fight it for as long as i could. but if things took a quick dive... then i'd say laters.
ThumbSucker: I also can't tell the whole picture to my family because it would be pointless stress that they couldn't do anything about.
ThumbSucker: part of it is that it's a cycle - they worry about it stressing me and they think the stress is the main cause of the increased headaches.
ThumbSucker: they only reason I mentioned I might be sick to my brother was that I didn't want them to be completely stunned if it turned bad quickly and something happened to me.