Regarding facing a similar situation and dealing with it, my mother-in-law
is 84, frail, has heart failure, and has a rectal prolapse. She has decided
to go ahead with surgery to repair the prolapsed rectum even though it is
high risk due to her heart condition, and there is no guarantee that the
prolapse will not return. The surgeon has told her that there is a 50/50
chance that the prolapse will recur in the first year. The alternative is
not to have the operation and remain incontinent of faeces, having to wear
incontinence pants, and in pain from the prolapse. That wouldn't be directly
fatal but would probably accelerate her decline due to the effect on her
morale of this living hell.

She has made the decision to have the operation on the basis that she has
nothing to lose; the operation might kill her but her life isn't worth
living in the state she is in. The family fully supports her decision.

From your description your husband is in a similar situation in that the
outlook seems hopeless if he doesn't have surgery, and there is a glimmer of
hope if he has surgery. What does he feel is best for him? Decline an
operation bearing the potential benefits (if any) and risks, delay an
operation bearing in mind the potential benefits and risks, or have the
operation bearing in mind the potential benefits and risks. Is he placing
the onus on you to decide, or has he made his decision but you don't agree
with what he has decided?