There had been always the typical brothers rivalry, MK wanted to achieve the higher as possible and David just wanted to have a band and play songs, not only playing but also writing songs and that, with MK and command, wasn't going to happen.
When David left DS, MK and John both played with David on his first record, even MK did a playback playing as rhythmic guitar for David for Italian tv.
Nowadays, when they are asked about what happened on DS years they say the same in different ways, that they wanted to pursue their dreams, but their dreams were different, and by what they say nowadays, it looks like both achieved what they wanted, in different levels of success, but both are happy with what they achieved.
If that happens, I can see easily both brothers playing folk songs, they have similar roots and his music had gone by very similar paths, but with very different levels of quality and creativity, obviously, but nowadays they have lots of points in common musically.
I also like when I read this David's interview, when he talks so honestly about fighting his own demons and facing all his problems, and the way he says about being happy with what he has, that there are always people who are in a better position that him, but also many that are in worse situation, so he's happy with what he has. It's the same position about how I face life, being happy with what you have and enjoy your life.
