Right to privacy? he is dead, no?
This appears to be the decisive point. It is posthumous. Nobody living, even if believed to be in the same position, has been publicly implicated.
Also this can’t be taken to a ridiculous point: if John Doe commits welfare fraud and is duly tried and convicted for it, the crime is now not a secret. Conviction implies that yes, the person was taking welfare benefits.
I know we have too many laws but this is where another law would make sense: you are committing welfare fraud if you take it and then fight for an enemy force. Now even formally, bye bye secrecy for these circumstances.