As I far as I understand your situation - "Your male friend (F1) left his wife (F2) alone here. And his wife will be illegal right?"

In my opinion, she will have a grace period of two months to leave back to Nepal. Unless her husban's F1 is terminated (like not being in university), the two month will not be counted. So try to join university soon and convert to F1 (it take more 1-6 months to do so).

Good luck