Find out a non-profit educational  organization in your States, they do lots of conventions. 

My fufu ko chora works at the bank, but can draw arts on Nepalese paper. And he is coming here. 

I found last month that there is a 3-day Japanese animation convention in  Virginia. I contacted them, 

showed all works of fufu ko chora, gave introduction of Nepal, bla bla, and it would be a great honor for 

him to attend this kind of convention from non-profit educational organization, and they wrote a invitation 

letter for my fufu ko chora. Thats it. I took responsibility of his staying in US. He got visa. He is coming on

October 15th for October 30-Nov 1, 2015 Anime USA convention. 

Hope it helps.