Nosey Mother

So my boyfriend has been living with his grandparents for years now just simply because they need his help. His grandparents sat me down the other day and offered for us to move into the basement and me to have all my animals at their house, (2 snakes, 2 bearded dragons, a hedgehog, a beta fish, two snails, 2 cats, and a dog. I have all of them here but the cats and the dog.) His Mother calls his grandmother and tells her she shouldn't let me have my cats and dog here and then tells me I shouldn't be mad at her for doing that!? Do I have a right to be mad? His mother doesn't even live here!