Great football players receive large, multi-million dollar contracts, right from the start. Many of them will also have a chance to receive money from advertisers and other promoters. If they're not investing that money (competently, if not smartly) to prepare for a time when they can no longer play, that's their problem.
Moderately good football players also receive million-dollar contracts, though not as much as the great ones. Invested wisely, those salaries will provide a comfortable living; name recognition can also help launch a lucrative second career.
Players who were drafted lower, or who have to spend time on practice squads or as backups to starters--they're still getting contracts that are worth hundreds of thousands per year. Hopefully, they're not being foolish with that money, realizing that their time in pro sports may be limited. They'll most certainly need a second career, but they have a chance to be very comfortable if they invest wisely.
What Mr. Brown should do is ask the owners to fund financial education for their young, and even older players. Teach them how to be athletic superstars, but also, financially-savvy ones as well. Then, they won't have to worry about a paltry $2500/month pension.
I know that the Cowboys provide financial classes for all new players to advise them on investing/saving. Perhaps all NFL teams do, also.