Considering the already destructive and unstable nature of Dimitri's abilities I don't know if mind breaking him would be a good idea, lol. Then again Kassy could probably get away with a bit subtle influence since he actually trusts her. I've sort of come to picture Dimitri to be sort of like a dog that's been used for nothing but dog fights, at least in terms of personality: He's extremely quick to resort to aggression since it's pretty much all he knows now, and takes forever to actually trust someone. Once you get him to actually let his guard down around you, you've got a friend that not only thinks you can do no wrong, but will lay down and die for you if he has to. That being said, he's still a bit leery about things like affection and praise since he's not really used to it.