No---that does not mean you cannot claim him as a dependent. Age over 16 will only affect the child tax credit. You can still claim a qualified child as dependent until they turn 19, or until they turn 24 if they are a full-time student. You can still claim a 17 year old as a dependent.
IRS interview to help determine who can be claimed:
https://www.irs.gov/help/ita/who-can-i-claim-as-a-dependent
https://ttlc.intuit.com/questions/3113432-who-can-i-claim-as-my-dependent
**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.**
