Without knowing a bit more about what he typically eats, we're limited in how much we can help. But I can offer a few suggestions off the bat.
First of all, it's great that he's incorporating exercise into his life. He needs to build that habit so he can stick to it for life.
Now, he really needs to eat more times per day. He can start off with 3 meals and work up to 5 or 6. Like midgetcop said, starving himself will only slow his metabolism. He'll have to do some careful recording of everything he eats and play around a bit to figure out how to create a slight (key word is slight)
caloric deficit.
The problem with a caloric deficit is that the body will break down muscle as well as fat to fuel itself. So how do we tell it not to break down muscle? We do
resistance training. Since he does not have access to weights, would he be willing to try some bodyweight workouts or something like crossfit?
Hope that helps.
P.S. If he has internet, please tell him he's welcome to join us here.