You can't defame a dead person.

Not entirely: https://strasbourgobservers.com/2017/12/08/the-european-cour....

I'll rephrase "can the family of the dead person sue people for causing emotional - and potentially financial - trauma due to people making false claims of criminal activity?"

I also get there's a glib "you can sue for anything, but it can always be thrown out" response, but that's a non-answer.

I understood the question and believe the answer to be “no”.