This is not a family owned business, although it sometimes feels like it

I work in his home though with two other people. I guess I feel mostly guilty because my yorkie is coming with me to work. So now I do have mine at work/his house and we put his JRT in a kennel...
I just had to take a stand this time, because usually he'll just leave and expects me to either find someone to take care of it or I have to myself. And I think it's just because he forgets and it's easy for him to leave it up to me. But every time I've put the dog with someone else, they tell me afterwards they don't want to keep him... So now I'm the only one... and I don't want to have him either
As far as the temperament, I do not trust him alone with my yorkie. Mine is pretty bold and will 'fight back'. She just doesn't have the strength to overpower him when need be. And I'm sure this is just rough play, as they aren't 'stiff', but the whole jumping on top of her, biting until my yorkie just snaps and gives him the 'crazy yorkie growl/bark' (while he keeps going), and taking every treat she gets (so he has 2 or 3, and she has none), drives me nuts! I guess I'm not a 2 dog person or a JRT person