For a moment there, all Neville could do was stare at the man as his hand gripped just a bit tighter around his wand. Honestly, he sounded like someone that should have been locked away in St. Mungo's, preferably kept far away from Neville's own parents. There were a lot of words going through his head that could describe this Dean person. Looney. Batty. Off his rocker. But, Neville hated to even think words like that. So he settled for something less offensive sounding, both to himself and, hopefully, to Dean.
"Are you feeling alright?" he asked, confusion written all over his face. Neville knew all about magic, that wasn't the strange thing. It was the fact that this bloke had come out of seemingly nowhere and started spouting off things about different dimensions (whatever those were), some bird named Lilith, and calling his robes a dress. They were, very clearly, not a dress.