He has such fine boning in his legs, I'm honestly not surprised he has hock problems already. The choice is yours, do you want him to be around for a long time, or do you want him to be retired soon? If the later, what will you do with him and where will he go? Because events like dressage, jumping, barrel racing, reining, roping etc are all hard on a well built horse. Let alone one who has such weak legs like your gelding. I would stick to light riding with him, either that or find another horse.