hi! i'd honestly suggest that the safest way to play multiplayer on this game would be either to play locally (ie with other users in the same room instead of online) or to supervise his online play if he will let you. i'm fairly new to this forum but i think that users here on TBT are fairly safe to trade with/visit/etc for the most part, but on other websites and communities there are people who will take advantage of newer players and scam them out of in-game items etc, or even worse
fortunately all the online parts of this game require having a nintendo switch online subscription so if you don't want to risk anything then he won't be able to access the online services at all. however so long as you're not adding strangers as friends i think it ought to be fairly safe for the most part - visitors have limited access to the host's island ie they can't use their shovel or axe to destroy trees/flowers and they can't pick up items which aren't purposefully 'dropped' on the ground.
perhaps you could help him post on here, or post on his behalf? you could both make a thread on nook's cranny to ask about trading specific items with other players, or make a thread on the airport saying you're looking for islands to visit and explore
this is very nice to see by the way! it's so good to have parents who are supportive of their kids' interests even when they're video games, lol. best of luck figuring out an arrangement that works for you both!
