There's probably another word that applies, but Optimus doesn't utter it. Maybe at another time. Family was hard to really explain to Cybertronians, especially when they're not of blood relation. It didn't work that way.

His eyes soften though, glad at least for that affirmation.

"Thank you, Rodimus. I loathe to admit it, but I can't be a Commander forever. But I'd at least like to talk. Once in awhile."