The game of hockey is like a family, you rely on your teammates on and off the ice and for high level players, including those in the National Hockey League, you see more of your team than you do your family in season. As such, the bond between teammates becomes extremely close. If something happens to one of your teammates, you want to honour them.
Dubois did Kivlenieks family if he could were the number 80 before he switched. Not only does Dubois have Kivlenieks with him every time he takes the ice, but he also said that if he were to ever win a Stanley Cup it would Dubois's last name but Kivlenieks number.