Hi there, can you confirm that you have gone over the rules with Arli and that he understand them? They can be found here.
Once you've confirmed that you've gone over the rules with him, one of the admins will add him to the whitelist.
We also have a discord server which can be run through a web browser or a client. Discord comes with voice and text chat so either you or your son can interact with people there, ask questions or chat about what ever. The discord server can be found here: discord.gg/rYXZ2Um