This describes me in the past. Don't let him date someone from HR, it opens up Pandora's box about relative value and standard practices with salary negotiation

This describes me in the past. Don't let him date someone from HR, it opens up Pandora's box about relative value and standard practices with salary negotiation. The largest factor for salary at most companies is how much you ask for rather than your skills or contributions. However there may be other things he values besides money. Continue to make those great and I'm sure he will continue to enjoy being your coworker.