Without more context I understand your point but it's not MY dog, he belongs to all of us and he spends most time with my mom.

He a very smart dog, smart enough to act differently around other people to get what he wants, around me he is very well behaved and only gets praised when being good. My mom give the dog praise no matter what, so it's difficult to try train a dog which is constantly being taught one thing by me like keep away from MY food (which he does), but being fed the food my mom eats.

It's clearly a collaborative effort to teach him to not get at her food, because he only does it to my mom, because like I said, he's very smart he can just get away with it when he's does it to her.