You could just report this on the surviving spouse's return and respond to any notices with a copy of the 1099R. Or, if the withholding is close to the tax due, simply ignore it.
I too remember Block's POM paying clients with the philosophy taught to us to explain to clients that when HRB pays an obligation of a client that HRB issues Form 1099-MISC. I wasn't involved in the 1099 issuance, so don't remember if the 1099 included ALL payments by HRB to include tax, interest, and penalty.
I guess the first question I should have asked was: did the IRA's have the spouse as a named beneficiary on them? It does look like the custodian screwed up regardless, if they knew the owner was deceased. Normally they would have requested the estate EIN if no one was named as a beneficiary.