I'll argue the case of mistreatment. Where as he's not doing it outright. He does:
1) Go behind his girlfriend's back to have sexual relations with her daughters (most women tend to frown on that)
2) Manipulate Lisa into sexual acts using her naivety against her (victims in this group are another debate)
3) He ridicules Alice shows to get more influence over what she does during them
4) He blackmails Kira into blows jobs if he catches Max and Kira in the tub (only because the smell of sex would make Ann suspicious, guessing that would hurt her if she found out)
5) Mastubates to Ann's naked daughter in her room (what Ann does not know can't hurt her, right? unless she finds out then we would know if it would.......

)
6) Frames Ann's son for theft to get him kicked out of the house (Parents generally don't like that)
7) After the breakup his true colors are revealed so now he's harassing her at work and threatened her that should she quit he'd make sure she'd never find a good job in the area again.
Did I miss anything? If you can sweep all those things under the rug I guess you can say he never mistreated anyone.