Why would he retire? He is only 24 years old and the concussion is really the first major injury of his career.
Many great athletes have come back stronger than ever from much worse injuries.
A concussion cannot be compared to any other injuries. Especially in hockey. It is almost a given that he as had multiple concussions that have gone untreated playing hockey. Its scary to think that after the first concussion you are at serious brain damage risk...