Jerry and Goober are alike in a number of significant ways. The similarities the two share help to bring them together, creating a mutual sympathy between them.
Both boys are "outsiders". They have few friends and are involved in a difficult process of finding their place in the school and in general. For these reasons, Goober and Jerry understand each other.
Additionally, they are both on the football team. Goober watches Jerry get hit as the quarterback and get up again and again, absorbing the punishment required of his position.
He can get up again after being knocked down and come back for more.
This punishment is extended to Jerry's position when he takes a stand against the chocolate sale, the school and the Vigils.
Jerrry continues to absorb the punishment demanded by his position, never giving in. Through his trials, Jerry shows a strength that Goober does not possess. This difference in character is clearly shown when Goober finds his sales report falsely inflated.
He does not speak up and rushes to his locker in tears, knowing that he has betrayed Jerry.
Watching Jerry edge toward defeat, Goober sympathizes with Jerry because he suspects that Jerry's strength will not be enough to save him.