Sorry, wrong post. I'm following 2 different tax related posts. Oops

He'd still be on the hook for what he owes.

I think you're probably right. I didn't think about the discrepancy between the return and the w2. If she e-files, the return might get rejected from the get-go. Either way, none of it is OP's problem.

Exactly. All you need to do is nothing. You didn't submit a false return. You've done nothing wrong. Let her do whatever she pleases. The bummer is that she'll likely get away with it. The IRS is unlikely to audit her.