One of the important safety strategies in hiking-backpacking is to let someone know your route, departure and return times. So if he's communicating daily travel information then his family/friends and acquaintances would soon know if something went awry.

His social networking probably has gained him acquaintances all over the world, which could also be helpful in his journey.

But I'd be wanting the usual backpack gear, as well.

A credit card, cash and passport will get one far in this world, as well. They'll also get you mugged in some parts of the world so an adventure it surely will be!