The retirement was not directly due to concussions. He is fine medically. Mr. Borland was worried about the long term impact of continuing to play and future concussions.
He played college and High School ball...he had prvious concussions....
Don’t know the specifics of the his case but its a personal choice....
I’ll never second guess a player on their own medical (or potential future medical) issues or decisions.....
Good luck to him....
Maybe he figured out they hit hard in the NFL, unlike the ladylike pushing and shoving he experienced playing in the “Big 10”.