Colin could never forget nor forgive his mother for putting him behind Keith and Joey.
He developed a mistrust and hatred for her similar to that Lucy and Nick, both of whom married at eighteen and moved out, had always felt.
Zena, who was three years older than Colin had never held the spotlight, never knew life was any different than what she lived. She had always come last, Colin had always come first.
When he was supplanted by Keith and Joey he learned what Zena had always known.
When Keith and Joey were gone, Colin, regained centre stage and Miranda had to work for his love, his attention.