He just seems well educated to me. He hasn't said anything that isn't capable of coming from a 16 yr old.
His naivety is what gives away his age. His behaviour is that of someone who wants to earn your trust and will do things that put him in the firing line by doing so.
Since his return I've noticed he's being a little more assertive and much less of a walkover which is good.
Call it projection but he reminds me of my younger self - always thinking the best of people and always hoping for the best of a bad situation and always expecting the other person to reciprocate in kind if you submit first. This attitude works only if the people you're dealing with have the same behavioural pattern but in reality, most people are out for themselves and will paint you into a corner quicker than you can turn your back.