You FIL sounds slightly like my father (for your sake, I hope not). But my dad used to feed our Min Pin table scraps and all of us, my mom, my sister (who is now a vet tech) and myself used to yell at him for doing it. We used to keep Kodi in a different room so he could not give him food while he was eating dinner. Of course Kodi would always go in after to clean up the floor around his chair. But that is much less than he'd get from my father.
If it's possible, keep the dogs out of the room during dinner.