PS: He claims the money was all used at the front end of her care.
After all the lawyers that have walked all over this, and the fact that the hospice is maintaining the body gratis (implying a means test for the patient's family), he would have to be a very clever man to hide a sizable sum that was a matter of public record from numerous courts.
Do you really think that he's enduring all this for money? This is a big load of harassment. Divorcing her and saying to her parents, "Here's the pile of receipts! Have fun with your vegetable!" would be much easier.