Thread:Tupka217/@comment-5065652-20171130143843/@comment-1038387-20171130151601

Not all relatives need to be mentioned, especially if they're only relatives because of a relation to another character.

I'm not sure whether predeceased parents are still legally in-laws, but I doubt it. Law only applies to the living. It also implies a connection: "my father-in-law" assumes that person also has a personal relation to you. If they were dead before you met your partner, there's no connection. They're simply "[partner]'s parents".