Bullshit or truth?

I'm having a new problem with Donny, and I can't decide whether or not to believe him. He does things that really upset me and then later claims to have no recollection of them at all. We're talking complete amnesia for the time frame involved.

Last night we got into a major fight. As in discussing how to divide our things when he leaves kind of major fight. He kept yelling and screaming at me. It was really bad. His level of anger was off the charts. I can't even find words to describe what happened.

At the end of the fight we decided to get a room in town since we had to be there today anyway. I agreed mostly because I didn't want to subject my family to Donny the way that he was behaving. We got to the room and he laid down and went to sleep.

About 3 hours after going to sleep Donny woke up and started talking to me. He used a normal tone of voice and was nice. It was as if nothing had happened. I flopped down on to the bed and burst into tears. According to Donny that was his first clue that something was wrong.

Donny swore that he couldn't remember anything from shortly before the fight until he woke up in the motel room. Then he started remembering "pieces" of the evening. He can remember going to the store. He remembers talking to the homeless guy. But he can't remember the fight at all.

I'm especially skeptical about his lack of memory because that's his excuse for not apologizing for his behavior. He's said a couple of times that he'd apologize, but he wouldn't know what he was apologizing for, and he won't apologize without knowing why. He refuses to talk about it and let me tell him what happened. I've managed to tell him a little, but then he shuts me down. From what he has heard he claims that I must have started it.

It's at this point that I want to tell him that he's full of shit. He's claiming that his medical problems are to blame, but I'm not so sure. I know that his brain is shrinking and all, but does that really explain all this? I wish that there was a handbook that could give me clear answers on stuff like this.