Is it normal my uncle acts like this after going out?

My uncle is seriously one weird dude. I'll tell you what I mean. He does this almost all the time. After coming home from going out for a long while, he completely changes into someone new, and someone I don't like. He won't talk to anyone, and what he'll do first is take his tablet into the bathroom, take his vaporizer also, and lock himself in there for literally hours. And once he finally gets out, he'll start talking to himself in front of the mirror in the hallway,and will start talking about "supposedly" experiences that happened to him, (which they never, btw) talk erotic stories, and the most annoying of all, yes this is true, rap. He literally does that all night and all day for maybe 2-3 days. And after he has stopped, he'll be passed out on his bed because he was up for days doing what he does. Then weirdly enough, once he's gotten enough sleep,he'll be his normal old self. The whole family recognizes this pattern, but we never had him treated or examined because he always manages to turn into his old self afterwards. So, anyone have a clue why he does this? And by the way, I know this sounds like I made this up, but trust me, I'm not.