Will the IRS accept my paper trail showing I distributed my brothers' portions of my decreased dad's IRA to them, though I am sole beneficiary & the 1099 comes to me?

I plan to send the IRS a statement signed by my brothers saying they'll be responsible for taxes on their portions, copies of the checks I wrote for their shares, their SS #s and a letter of explanation. My dad died before his living trust could be made beneficiary of the IRA, leaving me as sole beneficiary.