Odd wants to apologize to his father, Jeri, who (amongst a laundry list of other things Odd is sorry for) in a roundabout way gave his life so Odd could keep his.

With how awful Odd's self worth can be and with how much of a pedestal he put his dad on, his 'apology' would be something along the lines of:

"I'm so sorry I somehow tricked you into believing my life was somehow worth more than yours."