We have commissioned him to make custom music for our game but is not comfortable with giving us the rights to the music.
I have a question. When you say about giving the rights to the music, you mean rights of use and distribution or giving authorship? I ask because they are different things and that non-artist people often confuse as the same thing, and artists often don't want to give authorship (unless, sometimes, if it isn't for a really big $).