I would say it's definitely with in bounds. You might make sure you know cycling law as it applies in your locale.

Have a definite "conversation." if the opportunity arises. Have solid reasoning & patience. He may genuinely not know & is riding as he was taught as a pedestrian. Being "wrong" has a way of shutting people down & setting them harder. Your approach is 100% the key, & only then if the opportunity arises organically.

What he does after that is up to him.