I think I know this wise guy.
Yeah, I will print out the letter to the housemate tonight and leave it for him tomorrow and he can decide. If he feels uncomfortable about my fathers actions and my reactions are not enough to abate his concerns then I am best moving on.
It's not like I don't take his concern seriously, I gave my father his marching orders and I have disowned him which is heavy stuff. But it is how serious I take this matter and if that isn't enough for him then there is nothing more I can do but move on and this time, no share housing.