There is a huge gulf between looking after a long term partner and beginning a relationship with someone with health issues.
I would look after H until his final breath but we have two decades, so far, of a bank of memories.
OP are you ok with the no drinking, less stressful job type of guy? I think that is what you should ask yourself if this, whatever it is, could be a relationship for you where there is a lot more up than down?
Yes there are always downs in relationships but you ride them because the ups in between are longer and better.
It's not so much the health history as the possible proscribed, inflexible future that would be cause for concern.
As just as disclosure, no I wouldn't go out with anyone whose health was considerably worse than mine. But I am older, we have two dependents, I don't need another, apart from potentially their dad but he "has been told he can die when I give him permission which he is perfectly fine with we just bicker who is going to die first in the allocated 10 minute window".
I just don't have it in me to care for someone without the history. If I'm being honest. My parents never wanted me to suspend my life to care for them. I feel the same about our children. So anyone else just wouldn't happen.