That's what dear old's condition is called.
I went to the rehab center to see him, and on my way to his room stopped at the nurses' station to talk to someone. Yesterday when I was there, one of the nurses had asked me if he had ever seemed "confused" to us while he lived with us, and I said, "Not that I can recall." Today, of course, I said, "We had evidence of that last night." She nodded and said, "Good, I'm glad it wasn't just me," and went on to explain that dear old has had Jekyll-and-Hyde episodes: "One minute he's a very sweet old man, the next he's confused, and a little while later he's downright nasty." Yep!
"Ask him," she said, "if he remembers calling you last night. I bet he doesn't." And sure enough, he didn't! Apparently very old people get this thing called "sundowning," where they get phenomenally confused about everything in life once the sun goes down; and while the sun is up, they are their normal, rational selves. I'd heard of this, but hadn't realized it was kicking in with dear old.
Now I'm glad I kept my patience, and kept my visit with him friendly. Glory to God for granting me that patience, and the visit with the nurse beforehand; but these doctors, who keep insisting that living into your nineties is a good thing....!!!!!
When I got home, I called dh at work and told him the nurse said not to bother visiting his father, because dear old won't remember it. Dh was shocked, to say the least, but yeah, that's consistent with sundowning, too. Oh, and it's exacerbated by alcohol -- the smile on her face when I told her about the phone call, and his "tippling" habits (I wish it were only tippling!) was priceless. I feel bad for dh, but at least we know dear old really isn't playing with a full deck.