Let’s talk about it

So did Jichan know that was his father? Cause the Reverend (?) lived at the orphanage right? So it would make sense his son would too. I’m just confused if Jichan knew or not. Or was he an orphan and he adopted him? Cause speaking as an adopted child myself, adoptees tend to pick up on stuff their parents do, so it would still make sense they say the same things. I need to know