Recently, I've been trying to think of any quarterbacks who seem to have these problems, and can't come up with any.
Wait, I actually just thought of one - Erik Kramer. He just recently shot himself in a suicide attempt.
But, there have been a number who had to retire from too many concussions who seem to have done really well in post football life - Roger Staubach, Troy Aikman, Steve Young.
Even Jim Kelly seemed to have a lot during his career, though that's not what he retired from.