Who does the OP think he can sue?
Gail
Mark would not have a lawsuit against the hacker (although the father-in-law might and there could be criminal charges against the hacker) and Mark would not have a lawsuit against his father-in-law even if the hacker story was false and the father-in-law ignored Mark's plea for help. There are no damages.
He might want to see about family counseling. And buy a book on survival in the wild - should his car break down (on a main traffic route) again.
My brother-in-law bought military rations for all in the family one year and we kept them in our car for an emergency. One day we were stopped at a railroad crossing waiting for an exceedingly long, slow train to pass. The kids were hungry and screaming so we broke into the rations. Not
exactly the type of emergency the rations were intended for ... but it kept the kids quiet until the train passed.
The peanut butter, by the way, is like a sheet of peanut brittle. Not too bad.