I'd be happy to make a few recommendations here, yes.

Personally, I would just buy it from the Square online store: https://store.na.square-enix.com/final-fantasy-xiv

Steam should work fine, but I understand doing so would force him to buy any future expansions via Steam as well for them to be compatible with his existing account. Likewise, buying it outside of Steam will prevent him from being able to buy any future expansions via Steam. Steam can be a very useful platform for automatically updating software while you sleep, etc. However, due to the launcher-based nature of FF14, I don't think this benefit will exist for it. So you don't really gain anything from Steam.

Ultimately, what you're giving him is a product key. He still has to set up an account on the Mog Station site to play. That's where he can put in the product key to unlock access to the full game.

You should also use the "Recruit a Friend" program to ensure you and your friend both get the associated benefits. He'll need to enter the associated referral code after he makes a Mog Station account and before he enters the product key from the game you buy: http://na.finalfantasyxiv.com/lodest...riend_recruit/

Beyond that, make sure that you buy a copy of the game for the appropriate region. I linked the North America Square store there, but I understand those product keys are incompatible with accounts for Europe and Japan.

That just leaves specifically what to buy him. You can buy downloads (which effectively just email you the product key), and you can buy boxes with discs that need to be shipped. Beyond that, you can buy the "starter edition" that's essentially the game up to Level 50 for $20 or the "complete edition" for $60. The starter game and expansions are also $60 purchased separately. There also appear to still be physical and download collector's editions of Stormblood available.