Factual error: In the scene where Trey's father shoots at the burglar the gun punches baseball sized holes in the door. A .357 Magnum bullet going through a thin wooden door would just punch through, without expanding or tumbling, and leave a hole only a bit larger than the bullet diameter.
Factual error: When Furious goes to the open land with Ricky and Tre to give his speech about his job, it's mentioned about that location they're at being in Compton. They are at the bottom of a hill (due to the slanted street angle). There are no hills in Compton. Also a 27th St. Sign is visible. There's no 27th St. In Compton either.
Answer: It symbolizes that he used to be a football player just like Rick wanted to be at that age. But probably due to the cards he was dealt he gave up on that dream. When they emphasize the man in the feel its like showing empathy to the kids because he sees himself in Ricky, thus giving the ball back.