I have found that an excellent tool when writing fiction is to take some of your own experience and put it in a story. I do this a lot. Usually it may be that I base a character on someone I once knew, or I fictionalise a story that I have been told by a friend.
An old legend holds that immigrants from the Canary Islands brought a recipe for chili with them when they settled San Antonio in the early 1700s. Historians do know that chilli was a popular meal amongst cowboys and pioneers on the Western frontier.
You are tired of listening to your mothers-in-law voice, and can see your father-in-law is at his wits end. Perhaps some bondage type toys would work here. Maybe he would like to take back some control or simply experience some peace and quiet for a change. The perfect solution would be a ball gag!