Regarding whether he actually died or not, of course we can't be 100% sure, but here's what is said in the Jennifer Robertson Affidavit uploaded by Coindesk to scribd:
She's obviously lying. If he really submitted his will a week before his actual death there's high probability they were talking about death with his wife and that he told her about private keys.
I think they are blaming it on the dead man because it can't hurt him in his grave and taking all the money.