I've had sexual dreams about my father.
He also was an emotionally and physically abusive alcoholic.
While I do remember some inappropriate comments and some touching that I wouldn't class as abuse but kinda odd I really have no memory of him doing anything nearly as extreme as in my dreams. I just don't get the feeling that he actually did anything and I'm too scared to really think about it in case of false memories.
I was totally creeped out to the point where I googled it. If one is to believe dream interpretations then it is supposed to mean a yearning for a closer relationship with the person.
I don't get the impression that would be the case for you though.
Obviously I can't say whether or not you're having flashbacks but if you have a T you should consider talking to them. Hopefully they can point you in the right direction.