[There's an unamused looking kid in grey on screen, as in, that's the actual color of his skin. There is some sympathy lurking under that look, though - he's been there several times.]

People do just disappear. Check the contact list on your SFC; if he's not there, he's gone from this universe back to his, and there is absolutely nothing you can do about it. Searching won't find him, complaining to the network will get you nowhere, and yes, it is just as impossible to get anything from the natives as you said. It sucks, but I have doubtlessly been here far longer than you have, and I know how this crap works by now.

Also, if anyone you know ever does die here, they'll revive five days later and appear by the coral.