LOl you have just described my 5 year old son. Sounds fairly typical for the age, I know it's hard tho...they just don't mesh well with the little ones. Fortunately you only have til June, I'm in it for the long haul

My best advice is trying to make them feel a part of the group by giving them responsibilities. For example, my son helps me undress the dck when we come in from the bus run, and he actually likes doing it. Don't force anything, just try to find something he can help with. Even if that means dishes maybe...just take out the sharp stuff...he's a big kid so you have to treat him like one.