Alternatively, look for local bitcoin meetups and buy directly from people there. Could set your son up with a lightning wallet like Zeus or Mutiny and then transfer to a cold wallet later. 

Great opportunity to meet bitcoiners in your community, spend quality time with your boy, and teach him how to transact, transfer, and store his corn. 

If not meetups exist in your area, and you’ve got the moxie, consider starting one. 

Whatever you choose, it already sounds like your son has a good father who is setting him up for a strong financial future.