It's not really a copyright issue, more of a publishing one. Since you seem to indicate that you identify him as the author, and do not dispute his copyright, that seems to be pretty cut and dried.
The real question is, do you have the right to use his copyrighted work with or without his permission. If his work was licensed through a publisher, and registered with an organization such as BMI, ASCAP, etc., then you might not be able to use his songs without his (or his publisher's) permission.
I'm guessing there's no written contract regarding payment of royalties, or any method of determining how much he should get. These are issues that should have been decided before doing the recordings, to protect both your side and his.
You should seek out legal opinion, and not listen to the 'advice' of anyone not versed in copyright or publishing matters (including me).
Mike - Militant Left Hander
See profile for list of TB clubs I'm a member of