S.L.
Sounds like he doesnt know how to interact positively with other toddlers. He wants to play but like most toddlers doesnt know how to begin interaction. Model using phrases like; "Can I play too?" "That looks like fun" "Do you want to play ...... with me?" If he is not talking, continue modeling the phrases for when he learns to talk but add lots of gestures. Teach him the gestures for come here,sit next to me (patting floor) You could try teaching him to grab two toys and offer one to another child. Sounds like pretty common behavior at that age!