It should be no different than whatever he or she would've needed to come here as a F1 student if he/she were coming here from Nepal. 

Thank you footyfan for the response.

But from Nepal we have to show lots of different documents and I am not sure all of those is needed or not.

If we use same documents, that might be old when my friend got so does he need to again get more documents from Nepal?

He ( and I) is really confused.

 You need a valid I-20 and documents that'll 'prove' that you will not only return back to Nepal after the completion of your studies, but can also afford your college education in the United States. 

So you mean again he need to get updated documents from Nepal ?

Is there anyone who have just come from UK to USA or planning to come??

saanu_fren, it all depends upon his status and the length of his stay in the UK. Your friend should provide documents establishing his ties to the UK or Nepal. If he is a permanent residence of the UK then he doesn't need anything from Nepal.

Thank you hariybicep.
My firend is just in F1 in UK and it's been 4 yrs. So it might be little difficult, istnt that?