And he's trying to take on a parental role with you? [Mark frowns. He can understand paternal instinct, and he can understand a young adult's struggle to become independent. And he also imagines it's very hard for Chris to be presented with a father figure so soon after his dad died.]

He sounds like he really cares about you. But this is a boundary you're going to have to clearly put up – you're not a kid, and there's no reason you should be treated like one.