Whenever we visit my Husband's parents. My mom in law always took control of my son. She feed him, napping, etc. It seems like i don't have permission to touch my own son. I know she might missed her grandson but i feel powerless. What should i do?

Don't worry just chill! She loves him thats why she is doing things like this. Don't feel powerless instead feel relax that your son has such a loving grandparents. A child's child is always dearest nearest the most to the heart of grandparents. At home you are the one who looks after the child then for few hours or days let them take control and love their grandchild because they deserve it they belong to your son and your son belong to them. Kindly have patience and feel relax at least you will have some relief from chores.