H.B.
First off i would like to say i am so sorry to hear about your Daughter.When my son was that age we made a game out of it.we use to buy cherrios an would let him drop a few in the toliet and he would dunk em as he called it. we also use to have a big jar behind our toliet filled with his fav stickers and suckers and when he went he got to pick the prize. he loved it and within 2 weeks was totally off potty trained.I would also think maybe he is feeling a lot losing both parents is a lot on child.my brother was just killed in aug and my poor neice is going through a lot know and doing things she never did before. good luck and i hope everything works out for you.