Well you could try mtg but some horses genetics don't offer much in the way of mane or tail. My trainer owns a quarter horse who whilr she can get his tail to grow out his mane will never be spectacular. Posted via Mobile Device
I know mtg might be helpful, or I believe rice bran helps coats/ mane / tail. Also drtangle with your fingers and if possible braid it up take it out once a week run your fingers through it and put it back. That helped me with my old mares mane a bit. Posted via Mobile Device
Manes take a long time to grow out if he's rubbed it off it could be a couple of season till it grows back out. When we turned our stud out onto a new pastured with trees he could easily rub on he rubbed off his spectacular mane. It has been 2 years and it still hasn't recovered.