I am trying to book an award ticket and for my son (under 16). It seems I cannot book an award ticket with my son (under 16) without applying a separate account for him. Is it correct?

Ok, even after I applied one for him, it shows errors to my son's account:

• Your mileage is not enough for Award Ticket redemption. When your self earned mileage reaches 50% of the mileage requirement, you can purchase mileage to redeem Award Ticket.

I have sufficient miles (>150k) for two tickets (75k each), transferred from typ, and his account is a new one with 500 miles. Do I have to register him as nominee and transfer 75k to his account? I noticed that in some other threads it ways I can use miles from my own account to book tickets for companions traveling with me. Am I making something wrong here?

Thanks in advance!