Hi @ilosttheracoonjack , I sound like quite a similar man to your son, and I had a similar experience in my 20s that I thought I'd share.
I went travelling at 22 to Australia, with my brother for the first couple of months and then alone after that. Like your son, I'm not exactly a social butterfly. I've always really struggled to strike up and maintain conversations with strangers, so while I had an absolutely brilliant time, and did meet people and make friends while out there, I also spent quite a bit of time on my own.
Anyway, one evening a girl who'd been sleeping in the bunk below mine in the hostel struck up a conversation, persisted past my awkwardness and we just clicked. Sat up talking until 7am, and then did exactly the same the next night. I'd never just clicked like that with anyone before, and by the end of night two we felt like we'd known each other forever.
The only problem was that second night was her last is Aus, and she was heading off to NZ and then Thailand and Vietnam. We were both devastated, I took her to the airport, we had a tearful goodbye and she buggered off forever. We kept in touch over the next couple of weeks by email, and I hatched a plan that I could head to Thailand and meet her. I put it too her and she was ecstatic about the idea so I instantly sorted out flights and visas. I had to scrap all my existing plans, I was due to meet family in a few weeks and had work lined up in my next destination, so ruffled a few feathers when I cancelled stuff. My parents were also concerned that I was going off to a strange country alone chasing after someone I'd only known for 48 hours.
Anyway, I went, we met up at the airport and then spent 3 of the best months of my life in some wonderful places in absolutely wonderful company. The relationship didn't last, at the end of the 3 months I came home to the UK and quickly found a job, she went home to Israel and struggled to find one. We chatted online most nights and 6 months later she came over to visit me. It wasn't the same, when we went away for the weekend or whatever it was great, but at home I was working, she was rattling round the house all day waiting for me to come home. We made the best of it, but when she went home we both mutually decided to call it a day.
Despite that I wouldn't change a moment of it. I had 3 proper relationships before I met my DP of the last 20 years, and all of them had an hand in forming who I am now, taught me things about myself, some of it good, some of it bad. The one above though was by far the most important. It taught me that I was capable of spontaneity when I really wanted something, how to improvise. It taught me that with the right person, I was proud of who I was, I felt confident to be vulnerable and not have to hide parts of myself. It taught me what it felt like to properly fall in love, and to be loved in return. And it taught me that sometimes that's not enough, and you have to make an adult decision to do what's best, even if it goes against what you want.
6 months later, I met DP, and we didn't have the easiest start to our relationship. A month in I got her pregnant, although neither of us knew this until DP went into labour, and suddenly we had a baby. We weren't living together, were both fairly casual about the relationship, had busy lives so saw each other a few times a week. We had to have some hard conversations over those first few weeks, about whether we were going to try and make a proper go at it or just co-parent. In the end, it went fantastically and 20 years later we're still standing, but I don't know if I'd have handled it nearly as well had it not been for the prior relationship.