Having lived and worked in Buenos Aires since 2002, I've met a ton of interesting expats over the past 2 decades. These are some interesting stories and through it's a small world, I actually know your ex-friend 
@Vince!   Very very nice guy. You're right. He was one of the nicest guys in the world.  I had already moved out of Buenos Aires when I heard the news about him kidnapping his son.  I was shocked by it! I couldn't believe it when I saw it in the news.
It's interesting that so many expats here in Buenos Aires have drug or alcohol issues but I've also noticed that.   I was probably on the boring side in BA besides a glass of wine or so never drank alcohol or did any drugs. But I did notice that many expats here have issues. This friend of yours Vince I would also consider him a friend up until that incident. Never talked to him again after he kidnapped his son and never knew what ever happened to him.  I assume he went back to Australia.
I will meet up with expats on occasion but I don't really seek it out.  I did meet a few people on this forum.  I had a great chat and lunch with 
@GlasgowJohn and enjoyed that. We were connected on LinkedIn and I could see his background so I didn't have any reason not to meet up with him.  A few others are clients/friends of mine are on this forum.   Lately, I probably tend to shy away from meeting up with random strangers.
I have a ton of interesting expat stories over the years.  When I moved down to Buenos Aires I was still fairly young not yet 30 years old.  I had a very successful career building up a business and then moved here to start a start-up.  When I moved down here, there was no one investing down here.  It was shortly after the corralito and Argentina was in the gutter.  I started up a company for foreigners to invest here and I came across a lot of interesting expats.
I remember one guy was also fairly young. He was probably the same age or a few years older He might have been in his early 30's.  He did a consultation with me and I explained how to buy real estate here, how to legally move in money, etc.  I already had purchased several properties and he wanted to do the same thing.  He was in investments/finance industry.  We would go head to head on some buildings and I remember thinking to myself I wonder where he got all the money as he said he was buying for himself. Not some investment group.
I didn't talk to him again and a few years after that he bought a large building and was building a hotel.  Then I see in the newspaper that he was wanted by the US government and SEC for fraud.  He ending up marrying an Argentine actress here.  I think he ended up settling with the SEC. But I just laughed because I thought to myself something was strange.
Another expat I met was crazy interesting. He started the first strip club in Australia.  The guy was mega-wealthy. We became friends and I even visited him in Australia. There are a lot of interesting characters and expats here in Buenos Aires.