Bonding with my boyfriends son?

his mum keeps saying bad things to my bf's son and he doesnt talk or stand around me much...its improved over the last few weeks, i try to kick a ball around with him and stuff (hes only 10), but i get a bit quiet and nervous.i dont know what to say to him or do with him. plus any advice on what 10yr old boys like to do and eat would bre great. thanks for any help :)