Depending on their approach (motive), old guys can either be of real help or just plain get in the way. As a friend, mentor their presence can be invaluable- especially if they truly put the players above their own egos and past. I think there's only so much they can 'teach' however... these are gifted athletes. You either got it or you don't- that's what gets one to a 1st round grade like Gregory- not something that was taught. If a vet truly wants to help, they'll realize that, teach what they can but, mostly, just offer support, encouragement, constructive analysis... and get out of the way. It's a different game; always evolving.