Terrence and Phillip appear be to quite taken aback by the gesture themselves.
Kyle: I don't want a fighter, I want my mom.
Sheila patting Terrence and Phillip on the shoulder during the reprise of "Mountain Town" at the end.
The Mother's: (singing) Cause Terrance are Philip are sweet.
Sheila: (hugs the brothers) Super Sweet!
When Kyle hides Ike in his attic, he makes a promise to Ike to stop all the madness, get their mom to come home and become a happy family again.
A blink and you'll miss it one, during the La Resistance musical number, Kenny's dad has a picture of him on his helmet.
"Through the Eyes of a Child", the last end credits song. It pulls off the seemingly impossible feat of being a tongue-in-cheek Award Bait Song parody that retains the wit of South Park while still having a poignant melody and lyrics (about the innocence of children, or lack thereof).