How to handle my son's ego

I have a 3.8 years old son. We moved to US from India 4 months back. The problem is since coming here my son is missing home( India), especially people back there like his grandparents etc. He still keeps talking about going back; which we cannot for another year b'coz my husband's project brought us hear. The problem is that my child doesn't like going to preschool. Intially he was fine,(he has been going to school for 3 months now) but recently he has started to cry to get into the van. Today he said "shut up" to his van driver for putting him in his seat against his will. I was really surprised b'coz we have never use that word ourselves. There was also this incident previously, where he bit a fellow classmate on his arm for apparently  for wanting to use the same sink he was using to wash his hands. That was the first and the last time he did that. We talked to him about that and that it was not acceptable, he seems to have understood and hasn't done anything like that again.I try to get him to play with other kids in our apartment, but he doesn't like that too. There is this kid who comes to our house to play with him but my son doesn't like to share his toys with him. He doesn't go to their house either. He likes to play small games on the computer or watch TV.  My son has also had an ego problem for a long time. He doesn't like people other than family telling him what to do.(This is also the reason i guess he doesn't like school b'coz his teachers try to correct him when he is wrong) There r many incidents when especially in public places that when he falls or drops something, and people try to help him or ask if is alright, he starts to cry or shows anger towards them and demands to be taken home immediately. There is also this problem of potty training. I have been trying to train him for more than a year now but still he has accidents. When he is not busy he goes by himself, but when is very involved in a show or a game he wets his pants. I can understand that it a very big change for him with different environment and people but i would like some suggestions in improving his social behavior and potty training. Thanks a lot!

[greengeeny]

He is acting normal, and just misses home.  He is almost four, and it doesnt sound like of any of the issues you mentioned are consistent, or repetetive.  Besides not wanting other people's help, or being told what to do.  He is at an age where he feels he is capable of doing things himself.  Some children are not very good at expressing that they dont want someone else's help and can often sound harsh.  Try teaching him better ways to say he doesnt like something so that he doesnt sound so mean.