He should not stay in US without any proper documents. It would be a foolish thing to even think about especially since he has family back whom he'd probably want to invite in the US after he's settled. If he becomes illegal then not only will he go down but also his wife and more important his kids future. So, he should stay legally and if he can't then just go back to nepal and enjoy his life there instead of living here illegally. Even though a lot of people are here illegally, i bet you that 9 out of10 of them regret it, unless they don't mind having no life but just money. So don't even plan on staying here without legal documents.:)