I considered that possibility, but it does not exactly work because the original statement says "A son and father WERE in a bad car wreck." "Were" is a plural passive verb form, indicating two or more subjects.
Often we are asked to make a machine "work like this: (followed by somebody's ambigeous word description)". Word puzzles are good practice for figuring out all of the possible Boolean logic combinations for PLC programs.
If it said "A son, and father, had a bad car wreck" then it could be argued that it may have been only one man that got smashed. If it could be one man (who is both a son and a father) or two males (a son and a father), then how many possible correct answers are there?