He may be using the past to justify what he's doing. I don't know. Could you validate what he's saying and then let it go? I ask this b/c bringing him into the here and now sounds like this to me. "Limbo, you don't/didn't do X" and your response "You're right I didn't. I'm sorry I seemed so uninterested, but now I..." To me that's telling him what's changed, not showing him. That's just what it sounds like in my head, the reality may be very different.
As to lunch, well, I don't know. You could try once and see what happens. If you get resistance, back off.
