You can probably 'cure' him of his egg-eating tendencies in the same way that you can stop hens from eating eggs. There are several different methods, but one I've found to work is this: I lock the chicken up in a pen for several days (NOT with another egg laying hen). In the cage or pen, I place several fake eggs, that are filled with either rocks or anything else the chicken will not want to eat, and will hopefully find disgusting. Just having them locked up for a couple weeks or so away from any real eggs seems to make them forget about eating eggs entirely. May not work for your rooster, but if you want to keep him, you can either try that or any of the other methods to stop him egg eating.
I guess if you're selling him, whoever buys him can try to 'cure' him.