There are a lot of videos on youtube that will help you learn more about Axie Infinity. FOr the younger audience, it is better to have visuals rather than lots of things to read. I suggest "Axie on the Moon" as well as "Axie Explained" channels in youtube. Also your son should join the discord server of Axie Buzz and be active there :) Participation on the twitter of the community is a plus point as well. More importantly, he can also join here in HIVE~