I agree with Jay J and Steve as far as not painting it. Pepto Bismol Pink, your son is going to develop a psychosis or turn into a homo if you don't do something though. You might get arrested for cruelty for subjecting your son to that. Why not have him trade bathrooms with your daughter or you?
That said, since this is your house and your nickel, and nobody in this whole wide world would have a house with pink bathroom (except for that girl on trading spaces who wears a blouse 2 sizes too small) check with sherwin-williams as they might have a paint to cover tile. Press control and f and do a search on this website for tile. Seems like someone posted something about a paint or epoxy coating that covers tile and grout. Try a search on some search engines. No guarantee you will find anything durable. You might try a bathtub refinisher to see what he recommends. Good luck to your son. Hope you didn't name him Sue. lol