I've sent lots of clients to the local SSA office to get copies of their 1099s. In the cases discussed here, however, the clients are not able to go and there don't appear to be court-appointed fiduciaries who could get info from SSA or an IRS transcript. In that case, I'd take their last actual SSA1099, look up the increases and Medicare amounts for each year, and just file the return with the estimated numbers. If they're off, the IRS will send a correction if it changes the tax. They will also send a correction if withholding was off, so don't worry about it.