I think it might be fun for both of you but I'd strongly caution you against trying to teach him yourself. Suggest he sign up for a beginning class so he'll get an idea about what's involved and find out if he really wants to pursue this hobby. You will have something to discuss and you can be his "resident consultant" but you won't have the stress of being his teacher. If the bug bites, then he'll be on his way. If not, then he'll still have greater understanding of what you do AND you won't wonder if you did something "wrong" trying to teach him. It will be HIS decision whether to continue or not. If he does, he will undoubtedly begin to develop his own style and/or go his own direction in the hobby and won't feel "obligated" to do it YOUR way. You'll both learn from each other.
You might also suggest that he accompany you to a quilt show, on a "Shop Hop" or to your local guild meetings. Discuss the quilts in quilt books and magazines -- which ones "grab" his attention? what colorways does he gravitate to? (you both might be surprised!) People can get involved in hobbies in many different ways and trying to teach him how YOU do it might be too stressful for both of you.