Does a dependent with no income have to file a 1040x?

Question

My 25 year old son had no income last year.  In fact it was minus $6,000 on his 1040 form. I was fully providing for him.  His community college volunteers helped him file his taxes.  On his 1040 he indicated that "no one could claim him as a dependent". Because of that, I didn't indicate him as a dependent on my last year's tax return. 

This year I want to file a 1040x form for the last year and include him as a dependent.  I assume he also needs to file a 1040x to indicate that "there is somebody who could claim him as a dependent". Does he? Does he also need to file a 1040x?

Answer 1

The question reads "could", not would for a reason - you don't have to include him as a dependent if you don't want to, but if you are allowed - he cannot claim the exemption.

So yes, he has to amend and fix it whether you actually claim him or not. If you do claim him, it will be very easy for the IRS to notice the discrepancy and come to him asking questions.