There is nothing wrong with his tax return. I looked at it before I removed it. It shows he is being claimed on the Standard Deduction line right under his first name. Then he got the standard deduction for a dependent which is his earned income on line 1 + $350 instead of the full 12,000 Standard Deduction for Single.
So we don't know why your return is being rejected. Maybe someone else also claimed him on their return or used his ssn by mistake.
