Hannah had a long and outstanding career that led him to be the first Patriot inducted into the Pro Football Hall of Fame. I would take what he says *very* seriously. I hope your friend followed his advice.I had a friend in my gym who tried out to the then Boston Patriots camp as a defensive tackle. He was pulled aside by all pro offensive tackle, John Hannah. His advice to my friend was " If you make it on the Team, safeguard your money. Don't buy a big house or fancy sports cars. So many guys that I know only lasted 2 or 3 years in the NFL and are now broke." At the time John was driving a 5 or 6 year old pickup truck.
https://en.wikipedia.org/wiki/John_Hannah_(American_football)