I have played a lot of them, this is one of the few that have frustated me as much as did.

I’ve played both over 250 hours. My preference is thoroughly Xenoblade Chronicles X, as while I really enjoy the adventure of XC2 - it’s missing the vastness, the freedom (knowing that if you see it, you can go there), and the feeling of permanence - as in, I feel like a part of the world of XCX, something I don’t get from XC2 even close to as much. XCX to me feels like the more progressive and advanced game, while XC2 is more like a Xenosaga. Don’t get me wrong, I enjoy XC2 quite a bit as well, I wouldn’t have put all that time into it if I didn’t.
XCX has two major flaws though, 1. Its UI looks like a PC game. 2. It’s on Wii U.

XC2 is definitely more for beginners though. It’s VERY linear and handholdy like the first Xenoblade and the Xenosagas.

XCX is the wild west, you’re given a gun and a knife and you have to figure out on your own (with very little handholding) how you’re not just going to save civilization, but thrive in that world and make your place in it. While there’s some general bottleneck plot points, few people will experience the game the same way as each other. That’s a bit of a brief as to why I ended up so much more attached to XCX. Also, I like the story concept more than XC2: a city from Earth plunked down on an alien planet with alien humanoids and indigens - and you basically pick your role in society - the major conflicts which mostly revolve around your city - there’s a lot of mechanics and world elements that help lead to some emergent storytelling; but also a lot of built in sub-plots which all surround the development of spciety in these given conditions from many different angles. XCX is unique and much more appealing to me.

Aside from UI, and the fact that it’s on Wii U - the fact that Mitsuda wasn’t hired for the music feels like a flaw. They got some bigshot anime composer to do the music, and he REALLY didn’t know what he was doing with videogame tracks and made so much loud music in the game that it gave me a headache. Mitsuda opted for breaks with more ambient sounding stuff, and more strategically placed themes... although I do admit I got sick of several of the field themes - I think all daytime versions - luckily with XC2 you can control the volume of different types of audio.

Controversial - but I like the Breath of the Wild approach to audio better than any game I have ever played before, a strong focus on the atmospheric sound and music for appropriate locations and dynamically attaches to various triggers in areas, characters, and events. Very sparing on loud style music, though it exists for all the right instances. I found it as immersive as I found organic. I bring up Breath of the Wild because the game is closer to XCX in style...

A. It was minimalistic in the UI department.

B. It’s on Switch 

C. It BLEW it away in the audio department - basically the polar opposite philosophy.

If he love JRPG with deep story and fantasy themes as well as JRPG soundtrack then he can only choose 2

I think that 2 is better, but both are excellent games.
If possible, buy both, specially because XCX will probably be a very rare game in the future. If not possible, just buy XC2 and have lots of fun!

If he love JRPG with deep story and fantasy themes as well as JRPG soundtrack then he can only choose 2

To me, Pneuma is a great mix of both main heroins

I love western RPG's and JRPG's but i think i love JRPG's more i was always that kind of guy i also love anime a lot ... 

But what did you mean with XCX is about gameplay ? are you trying to say XC2 is less about gameplay ???