The bank was delayed in getting the RRSP turned over from his late wife to himself, which is usually automatic from spouse to late spouse. This is why doing my late mother's estate was easier than Dad's. Everything just turned over from her to him.
You must file a tax return for the deceased. I had to for dad. It wasn't easy. Not when you are in mourning. Our Allan Turnbull, in Bala, was an amazing accountant. He provided us with much advice. As was my dad's lawyer.
Someone's head should roll.
You also need to get a letter from the tax man, stating that the proper taxes were filed, and the estate is cleared, your job is over.
He can blame the bank, but please, people, find the right professionals to counsel you.