What a beautiful vocalist.. so many melodies with his voice.. do you think that he can sing like this without vocal lessons?
I was just listening to this song as well the other day. Gorgeous song. He has beautiful melodies and a passionate voice. It really makes a difference compared to certain vocalists.
Concerning your question... Russell Allen of Symphony X who has a similar style to Tom Englund, he mentioned that he received no training but he was quite familiar with harmony.
Honestly, I think it comes from practicing and trying different techniques on your own. However, I would reccomend knowing at least proper breathing.