No, you don’t understand.
Gai is Kakashi’s best friend, Gai is to Naruto as Kakashi is to Sasuke. Gai is the only person Kakashi accepts as his rival, as well as his last tie to what used to be a normal life for him. Now that Obito and Minato and Rin are gone, Gai is essentially all that Kakashi has left.
If Gai dies, Kakashi will have no one.
Dammit! I didn’t even think of it that way!!!!! CRYING! 😭