Well I guess you know the answer.... It's not healthy for you to have him around and he's a bad influence on the other kids .... Maybe he has ADHD or something similiar but term them and start enjoying your days again ..... They may be nice parents but it's their child so let them deal with it. Suggest he might do better in a center where there is more then one adult. But you just have to do it. When they pick him up next tell them you have decided that current arrangement is not working and you feel he needs more one on one care then you can provide him and tell them when the last day of care will be and have a letter ready saying the same thing. Just do it quick like a band aid !