logging out unexpectedly

This I my son's account. He can log into the world "my BIG house" on his game but once he gets in the game will sporadically suddenly log him out of that world. His house was/is on fire he is worried that he will lose everything. Can you please help fix this glitch? He has aspergers (Autism spectrum) and this is something he likes very much and plays. It helps bridge the social/communication gab between him and other kids his age.