It was also in the best interests of sportsmanship to all competitors not to give favor to his son. Unser Sr. also knew his days were numbered as a competitive driver on the circuit, while he knew Unser Jr. had many years ahead to have another chance at the title (Al Unser Jr. would indeed win the championship twice - 1990 and 1994).
It was in the best interest of fair competition for all participants not to show favoritism to his son. Unser Sr. also realized that his time as a competitive driver was coming to an end, while he acknowledged that Unser Jr. had many years ahead to compete for the championship (Al Unser Jr. would indeed win the title twice - 1990 and 1994).