The fee for using TurboTax is not based on the user's age. It is based on the complexity of the tax return and on which version of the software you need to use. Did you try starting his return in the Free Edition? You can clear and start over in the Free Edition if his return is a simple one.
If you have not registered, paid or e-filed you can clear and start over in a lower version of the software.
CLEAR AND START OVER
https://ttlc.intuit.com/questions/2586254-how-do-i-clear-and-start-over
https://turbotax.intuit.com/personal-taxes/online/free-edition.jsp
No age doesn't matter. What kind of income did he have? Can he use the Free Edition?
Why do I have to upgrade from the Free Edition?
https://ttlc.intuit.com/community/upgrading/help/why-do-i-have-to-upgrade-from-free-edition/00/26379
Or try the IRS Free File program
https://www.irs.gov/filing/free-file-do-your-federal-taxes-for-free
https://www.irs.gov/filing/free-file-do-your-federal-taxes-for-free will have options where he can file for free.