I had this happen to me when I was 14 , thinking I was tuff I played with no mask or eye protection, I was peeking around a tree that BAM! all I remember is a spit second and the pain........ I could not see out of my eye for 3-4 days then it started to heal and it started to come back slowly, if he has no nerve damage it should heal just fine over time. I wish you the best.