4 year old wont stop pooping his pants

[henderal]

I have a 4 year old stepson who has been potty trained since he was 2 all out of no where he started pooping his pants. he will say he has to go and he'll sit on the toilet for awhile and not go, 20 mins later he'll go in his pants. he is with us a week at a time while with his mother he gets passed around from grandparents to grandparents and her he doesn't do this anywhere else, but here. he does have a little sister here who is one. I still just don't understand. I've been told its a control thing because we are the only ones with a set of rules. he gets to do whatever he wants everywhere else. someone please help we don't know what else to do we have punished rewarded and so on and so on. I'm ready to put him in diapers again


This discussion is related to 4 year old son messing his pants.

[henderal]

no its not that, and i do know here is the only place it happens at. we have talked to his mom and grandparents and daycare They all think we're crazy and making it up. His mom didn't believe us till he said in front of us all yeah I do it and laughed. all she said is well dont do it again and that was the end of her conversation with him.

[RockRose]

First,  I don't think you should necessarily believe he doesn't do this anywhere else.  In divorced families,  games are played all over the place.  

Since he is very willing to sit on the toilet and try,  I think you should look elsewhere besides he's doing this on purpose.

Sounds like encoprecia to me.  Does he have a history of constipation and very picky eating?