Totally get that it’s a crime and punishable offense, but let’s say (hypothetically) there is a steady history of proof he made payments to the account (credit card) via his own bank account and/or had proof of cash or check deposits to her bank account(s) in question… would the argument of a shared account/funds hold up in court then?
no. Unless it was a joint account with his name on it, if the account holder dies someone cannot access that account in the days after death. Black-and-white.