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.