The attorney may have provided enough information. But as I discussed earlier, the bank would have had no more than 5 banking days to get a hold on the account in place, and that may not be enough time. Moreover, the bank can point to the father’s and the estate’s delay in notifying the bank that he was divorced and the POD was no longer effective as contributory negligence. Had your father done that while he was alive, after all, this never would have happened. Or the estate had gotten in place timely and acted to notify the bank earlier this would not have a happened. So even if a jury says the bank was negligent by not acting in the 5 bank days it had (which is by no means a sure thing) the bank might still win on contributory negligence.
The ex-wife, on the other, had no right to the money and it should be more straightforward to get a judgment against her for its return. You’d likely sue both at the same time, but I think getting a judgment against the bank under these facts is kind of a long shot.