op if it is a comfort to you at all, I am visually impaired and did an exchange program in Puerto Rico at 19, although it was with my university, I did have to go on my own. I was living in the US at the time, so not too too far to go, but it was a different language, a different culture in a lot of ways, and a very difficult environment for a very naïve 19-year-old like me to handle. Looking back on it, I learned so much, but it didn’t have the best ending, just because I was too young to handle a lot of it.
I would say, if you can try and get to know his friends as well and just trust them to do the right thing and be OK. Even if you can’t get there if he does need help, you can always contact him on FaceTime or Messenger or whatever app he uses, and try and work things through that way. Also, don’t forget there are embassies and consulates abroad, that if something really serious does go wrong, can’t step in and help. There are also a number of foreigners from the UK who live in many different places around the world, and many of them are friendly and will give a hand if needed. You just have to ask. So, if worse comes to worst, keep those things in mind.
I think one night away with friends may be a good start, and he might do more with his friends than he does with you, I know I certainly was like this when it came to my mom being over protective with me when I was younger. So maybe, you can think of some strategies with him, that he can use if he does get afraid to board the plane, but ultimately, I would say maybe let him face his fears and take on the challenge.
I am an extremely nervous flyer, and having a disability and having to cope with airport staff, some of whom can be really nasty, it’s very difficult for me. I always take something I like to do on the plane, so now it’s Lego, crafting, whatever I can bring, chocolates or things I like to eat, a good audiobook etc. also, some airports can be more difficult than others, and can be more user-friendly than others.