My pop's senility....

It's actually quite amusing really, my pop's senility. Some days he's as spot on as he ever was. He's as cranky and ornery and nasty and mean as he was back in his prime and he'll tell me I'm a "stupid animal that should go somewhere and die". Other days, whether he forgets that he hates everybody or he starts to feel his own mortality and feels pretty shitty about treating those around him like crap (I believe it more to be the first), he's been having moments where he's tolerable. On those days he just says that I'm "a stupid animal" and I don't necessarily have to go anywhere to die, but I should go make him a sandwich. I never do, because quite honestly, he'll forget he asked for one anyway. Not only that but, yeah. I don't think so. If he wants a fucking sandwich, he can make one for his damned self.
Watching his mind crumbling has been quite entertaining, but it's also rather frustrating because he really does forget everything. He gets confused easily and he lashes out, he loses things and most often times he'll yell at me for "stealing it", I have to answer the same damn question 40 times until he forgets what he was doing anyway.....
Most days, we go without saying anything to each other. He communicates via email and sends me the list of files that need to be whatever, or the changes that need to be made to something or forwards the whatever that needs to be translated from one language to another.......... from the other room. I prefer it that way. We can't stand each other and after the fifth or sixth spoken word, our conversations usually go very south from there and we end up in rather heated arguments.
It's great though. He knows he can't do battle much any more and I will go for low blows and jabs and bombard him with the whole armory, which is VERY disorienting for him and he backs down quickly. My mom always tries to make me feel bad for defending myself, but she's learning to think better of it these days as she is not one to face my wrath any more either. They've come to understand that I won't take anyone's shit any more, especially not theirs.
I know that there will come a day when the frail old man will wither completely. I also know that it will come sooner rather than later. Will I go through a grieving process? Of course. He's my pop and despite the fact that he's a sorry miserable excuse for one, I've only got the one. But of course, I think I did all of my true grieving in life and healed after accepting that. In the meantime, I put up with whatever the day brings with the crazy old git and we try to avoid each other as much as possible. It's a miserable existence, but it's what we have.