yep i second that. the new leagues about to start within a weekish, i suggest your son to make a new FB account, then you invite him via the game so you guys have a much higher chance to be on the same server. just make sure he waits for your invite BEFORE starting. havent really tried inviting via other play methods so i wont comment on that
annnd heres a tip, send gifts and play friendlies with hard defending/easy tackles for both of your teams to get a good supply of candies
do note if you guys watch each others games it doesnt usually mean an instant win