derivative music

My husband has written lyrics to previously recorded instrumental music
(ie, Kenny G, Dave Koz) and has recorded his singing of these derivative
songs. What is the next step, as in getting permissions to market this
CD? Any help you can provide would be greatly appreciated.

I am a law school graduate. What I offer is mere information, not to be construed as forming an attorney client relationship.

This is a derivative work. He would be able to copyright only his lyrics and if for release as a commerical product, he would need to get a license for the instrumental part (i..e permission from label/music publisher).

http://lcweb.loc.gov/copyright/