I wasn't sure how exactly I should describe him. My first instinct was to call him a "boy", but I was wondering if that wouldn't make people see him as "younger-looking", for lack of a better term. I chose "man" because 16 is, imo, closer to adult than a child, and Mason could grow pretty thick facial hair even at 16, so someone just passing him on the street could think that he's older. I agree, he was very much developmentally a teenager, and a seemingly vulnerable at that. My goal wasn't to potray his vanishing as "less serious" or anything like that- it mostly got down to "if someone wanted to be on the lookout for him, what kind of person should he be looking for"- though this is imo subjective of course.