Receiving a form 1099-r from the bank

So my mom was the beneficiary of my dad's  IRA.  She received a 1099-R from the bank. The letter from the bank came addressed to her like such- Jane Doe Beneficiary of John Doe. The 1099 is on my dad's IRA she had inherited but had left in the bank all these years and had just rolled it over actually. Well she passed away and had not touched NONE of this IRA. Apparently the beneficiary was her grandson (and I guess he withdrawn it all out the bank) but the 1099-R is coming back on her for the taxes for the full amount of this money instead of him. As executor over her stuff can I not submit a new 1099 to the IRS with his info on it letting them know he was the one whom received the money and he should be paying the taxes on it? I'm kinda freaking out here because this is quite a bit amount of money that she never touched nor was she old enough to start making withdrawals.