If you take a little kid to a restaurant you are responsible for either entertaining them enough to sit, or taking them for a little walk during the waiting periods. If you also brought your inlaws, that walk is a win-win.

It’s also a good idea to have them “help” you cut up their food, as much to keep their hands busy as to teach them how to use utensils. If you really want to stretch it out, because they eat fast and then get bored again, have them “help” cut yours as well.