It's a nasty one. If they got advance credit for health insurance and their income is above 400% of the poverty level, they need to pay it all back. If it's somewhere below that but still on the high side, they may need to pay some of it back. I've seen paybacks as high as $25,000. You mentioned 1099's which is a clue your client is self-employed?? If you link the 1095-A to the Schedule C (bottom of 1095-A worksheet), ProSeries will automatically calculate the self-employed health insurance deduction. This will help your client out a little. If he's not self-employed, then there's a small chance it will help out on Schedule A, if he has enough other deductions to itemize.

And as was mentioned, don't even try to file without it. The IRS WILL NOT accept it. They have the checks and balances in place.