A friend of mine happened to mention that her mother-in law was 87, was in a nursing home with dementia, and was diabetic. She likes chocolate cake, so my friend and her husband take some over to her when they visit.
I can fully go along with that. At that age, and with the other things going wrong, I too would place her pleasure ahead of her sugar levels.
I happened to mention that a few of the stroke survivors I've seen have been smokers. I just shrug my shoulders at this, for exactly the same reason. Whatever gets you through the night. Having a stroke is a shitty experience, more often than not you're left disabled, so if you can derive some pleasure from smoking a cigarette, go for it.
Interestingly enough, my friend disagreed. I mention it because it made me think - exactly how did she see that giving somebody chocolate cake (known to be bad for them) was different to somebody smoking (also known to be bad)? It seems to me that you're storing up long-term issues for a short-term gain.
I do like this friend but sometimes they say something which surprises me. None of us is immortal and I do think that there comes a time when it is appropriate to give up on life.