If he is not a dependent then he should not be listed on your return at all---you need to go to MY INFO and delete him. But, if you already e-filed and used his SSN on your tax return, he cannot e-file. He will have to print, sign and mail his own return. Or he can try to get an IP Pin and try to e-file. Waiting for your amended return to be processed will not help him at all.
GET IP pin in order to e-file if your dependent’s SSN was claimed on another return
https://www.irs.gov/newsroom/irs-takes-steps-to-help-prevent-refund-delays-by-accepting-duplicate-de...
https://www.irs.gov/identity-theft-fraud-scams/get-an-identity-protection-pin
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**