What should I do with the money my husband found, given that he and the original owner have both passed away? Should I give it to the original owner's wife, or should I donate it as charity on his behalf?

The lost item must be returned to the owner's heirs, specifically his wife, so that it can be included in his estate and distributed among all his heirs. Giving it away as charity is not sufficient as long as it is possible to hand it over to the heirs. The husband must seek forgiveness for keeping the lost item after knowing its owner.