However, at times, it is shown that Zim thinks of GIR like a little brother. GIR, despite being defective, is devoted and loyal to Zim, shown mostly through his rare moments of clarity, or in some insane fashion such as wildly attacking him with hugs. Zim is often shown trying to steer GIR in the right direction, even if he states that it is for the good of the mission. GIR simply tries to get Zim to have fun every once in a while, despite the fact that Zim refuses to do anything for his own benefit.
GIR is often able to bend Zim to his will. Despite often being harsh and stubborn, Zim is known to allow GIR to get away with some of his antics.Zim lets a teary-eyed GIR play amongst piles of their rubber pigs after giving him a firm "No" moments before. Additionally Zim forgives GIR surprisingly fast after getting them stranded in the city when he is faced with the weeping robot.When Zim escapes the Nightmare version of Skool, he expresses concern for GIR's safety, saying "I only hope poor GIR is all right by himself".
P.S.
I got this from GIR and Zim's Relationship(Invader Zim Wiki)
GIR is often able to bend Zim to his will. Despite often being harsh and stubborn, Zim is known to allow GIR to get away with some of his antics.Zim lets a teary-eyed GIR play amongst piles of their rubber pigs after giving him a firm "No" moments before. Additionally Zim forgives GIR surprisingly fast after getting them stranded in the city when he is faced with the weeping robot.When Zim escapes the Nightmare version of Skool, he expresses concern for GIR's safety, saying "I only hope poor GIR is all right by himself".
P.S.
I got this from GIR and Zim's Relationship(Invader Zim Wiki)