That's an incredible story. Do you know where he is now? It would be great if he found some profession that played towards his unique set of interests.
He still plays folk music, and regularly play at a Viking (Scandinavian) restaurant named Aifur in Stockholm. It's a cool restaurant worth visiting if you're going there one day =)
If you're in Stockholm and interested in Viking things, take a trip to Birka. There's a ferry from Stockholm. https://en.wikipedia.org/wiki/Birka