Is the 10 year old not old enough to go home on his own - maybe have a high school boy come and hang out with him, take him to play sports or run off some energy somehow. He is definitely too old for the daycare group if he is going to be as disrespecful.

Sometimes if you deal with the little ones - in this case the 4 and 5 year olds to get proper behaviour out of them then the older one backs off because it is no fun if no one plays along.

Maybe a couple well timed "shut ups" "knock it off now" would actually help. Time to be nice is over.