Your nephew sounds like he is a man now or at least over 16.
So I cannot see him wanting to come anyway.
What do the older generation and the uk have for a wayward teenager not a right lot.
Would it not be easier for you to visit the usa in a few years and just do a quick visit and some travelling.
Familes are awkward territory but you do not have to put anyone up or pay for them just keep in touch .