This time I am posting for info regarding issues of my friend. 

My friend is in Nepal. His girlfriend is in the US, she has a US green card. Now, what are the possible paths for his immigration to the US? They want to get married asap but the girl don't want to travel to Nepal because she has no relatives overthere. Please suggest all the possible ways for him to come to the US and acquire green card. Also how long it takes to process ? Please please help!!! Eagerly waiting for answers, thank you very much for reading and trying to help...