legality of contracts

Here's a very interesting dilemma that I came across just a few days ago. My friend, a new nurse from the Philippines, asked me about the legality of his contract.
Here's the story: My friend applied with a Filipino agent based here in the US. He paid $6500 dollars to get everything sorted out and eventually land a job here in the US.
In his eagerness to get here, he signed the agent's contract, part of which stated that if he breached his contract, he'd have to pay an additional $4500.
That contract was separate from his employer's contract, which had a milder penalty of $1500 plus the amount spent for the processing of his papers.
Again, because of his excitement, he didn't even bother to research the place he was assigned to work in. Like many of us, we used to say in the Philippines, "bahala na kung saan mapadpad, basta nasa Amerika."
Anyway, when my friend got here, he found himself in a desolate place in the midwest, where tornadoes are common, and where there are more pigs than people.
Again, like many of us, he endured the isolation as much as he could, until he finally caved in.
After a year (and after much prodding from his friends), he finally decided to leave. Because of his impressive work ethic, his employer agreed to let him go in good faith, and in fact waived the penalty fee. He, however, was asked to reimburse the processing fee. So after settling his dues with his employer, he left for a better place.
Soon after his left, his Filipino agent got wind of his transfer, and reminded him of the other contract, and that he needed to pay her (the Filipino agent is a female) $4500 for breaching.
He had saved up some money, and so agreed to pay $1500 initially and then settle the rest through staggered payments. However, when his friends heard about it (me included), they began to cast doubt on the legality of the agent's contract.
I'm no lawyer myself, so in ending my story, can anyone share their input about this scenario. Does my friend really have to pay out this other contract? Thanks!