Next time you go over if the yard is fenced in have your mom put the dog outside before you go over. When you get there have some treats like cooked chicken. Throw the dog a few pieces. I don't mean the whole piece at once and certainly not the bone. This way the dog will see you as a friend. It will probably take a few times of doing this but eventually the dog will catch on and will probably look for a treat every time you go over there. If the yard is not fenced in then make sure the dog is outside on a leash and do the above.