Paypal does not allow account holders under the age of 18. PayPal asks for a birth date when you register so whilst you can make a PayPal account with false information the account will need to be verified to accept funds into your balance or lift any limits. As he would be unable to verify his account it would be locked for further use. Minors can’t enter legal contracts so he won’t have any recourse to get his money back until he was 18 unless Paypal were happy to release it to a parent or guardian for him. Tell him to consider what his goals are in the long-term so that he doesn't back himself into a corner.
Advice is voluntarily given. Kudos / Solution appreciated if I helped you.