REASONING AND BEING STUCK ON PAST EVENTS

Hi there my adult son is at uni doing his masters in Law he lives at home with the family , long time ago him and his dad had several disagreements with each other and my son rarely speaks to his dad now .My son is 22 he likes to think he can rule the house and he likes everything done when he says so he a big lad 6ft 4 some times there is just no reasoning with him and he loves nothing better than to bring up past disagreements he has had with his dad , he gets stuck on these and won't let go of the past, he also refuses to compromise  on anything and has been known to say things to other students about me abd his dad and uses it against us saying other students hate us and are disgusted by us and we are very manulipulative, how true this is in terms of what these so called other people have said about us is I don't know . I don't know how yo handle this anymore , anyone have any advice please .