You have every right to vent if you want to call it that. I don't live in the same place as my dad, who lives a mile away and lives alone ever since my step mother died. I did all kinds of errands for him, drove him around, and favors for him for one year plus. I got vileness from him and thanks from time to time. The more I did things for him, the more he figured I must be some kind of dim bulb for being so helpful. That's how some people operate but it's a shock to see your father go that way late in life. I had always gotten along with him.
These old coots have a way of pushing one's buttons. They can be geniuses at that. You mentioned smoking.
There are lots of well disposed old folks. My father isn't one of them. I told him to shove it last month. Time will tell.
Regardless of how these old folks behave, the Bible tells us to HONOR our mother and father, even if they are vile creatures (my spin), so that things will go well with YOU. It's one of those tough scriptures we would like to avoid but... nobody said it was gonna be easy.