You can do it all online, I did, and all you have to do is create a bceid login for him, then you can create a new profile on the hunting services site. Once you create that, you upload a picture of something like a birth certificate or bc services card showing proof of age and then ideally also a image of your DL which has address (proof of residency). That's done in the apply for credentials section. They'll review all that and then when you're back on the main page you'll see his new FWID and buy the youth license. As part of that you will have to electronically tick/sign the responsibility of undertaking and you're good to go.
No more need for paper out in the bush, just note his number somewhere as you'll need to know it.
Gary.