is he best to downgrade to 9.2 and get a gateway or is there another solution/another emunand? and if so whats the best thing to do
Downgrade to 9.2 and use a custom firmware. There are debates on whats better, but they all perform well enoigh if you just want to play games. There are various threads already about how to do the entire process, give the forum a quick look and see what tutorial thread would be the best for your friend to use/understand based on their skill level.
I personally use rxtools for my o3ds. My emunand is fw 10.6 iirc and my system nand is 9.2. Theres a whole thread about nightlies and stable versions. Mines a bit older, but it works well.
My husbands n3ds is running reinand. Similar setup process, theres quite a few dedicated help threads as well. Again, 10.6 emunand and 9.2 sysnand.
Always use emunand. If youre really worried about accidentally updating, maybe try out that new thing, arm9hax something or another. I havent done it myself since I have no issues with my current set up, but its appearently really safe if you follow a guide, and it can save you from soft bricks if theres any problems in the future.
I personally have homemenu hax set up to launch at boot directly into my emunand with my own custom splash screen. I set it so that I cant accidentally get into my system nand and update. It requires a very specific button combo to get in, lol.
Good luck! I wish I could give you links to tutorials but im on mobile. Thankfully, the guides are all super easy to find here, and downgrade information is easy to find on "that iso site" please be sure you grab the right update pack for your console and region. The only bricks I have seen have been user error; So its safe so long as you're following a guide. Ive done this to 5 different systems now, so I can vouch for its safety and simplicity.
Edit: if your friend has money and doesnt mind waiting, sky3ds appearently works without downgrading