I looked at that POA form yesterday and it appears that the taxpayer has to sign it. Which he can't because he's legally disabled from making financial decisions. This is a common catch-22 that I've been able to get around, banks like to do it as well. Looks like the second page has info to report that I'm a family member representative, but I'm not sure if it would still require my dads signature (that he can't legally give) to be in effect.
So in the absence of a method to handle the previously paid interest, do I put all of it in, write a letter and just staple it on the front of the return, and pay the correct amount or pay the full amount and wait for the wheels at the IRS to turn and refund a portion of it as already paid?
