Iroh's relationships

Zuko
Iroh has always cared for Zuko. After his son died he thought of Zuko as his own. Iroh stuck with Zuko when things were good or bad. "In The Waterbending Master" Iroh showed great sadness when he thought Zuko has died.

Toph
Iroh met Toph by accident in the episode The Chase when she used earthbending on him. The two quickly made up. They had tea and talked about Toph's relationship with Aang and the group, as well as Zuko. They became friends and when Zuko was captured in Ba Sing Se Iroh came to her for help.