boyfriend aggressive in sleep after drinking?

[Tia M]

this may seem strange but, my boyfriend who is thirty years old is a nice guy, who also never shows any sign of aggression whilst drinking, until he goes to sleep. he always has weird sleeping habits of talking and such, but after drinking when he goes to sleep he becomes downright aggressive. fortunately i am able to ignore it on the most part as some of the stuff he says is simply amusing. when he is so angry that he simply cant think of words to say and just starts making angry funny noises, but after a while it gets plain annoying. it is so different from how he acts when he is awake, even drunk and awake. and rest assured it is all words and no action. but any ideas on why this could be happening and aside from stopping drinking what we could do. i tell him about what he does and he never ever remembers a thing of what he has said and always says that is so weird because it is not how he feels at all. he is now willing to go see someone such as a psychiatrist because he hates that he does it and upsets me. he also has quite bad sexsomnia (its a real thing honestly, google it) if that would make a difference.