The same way he orders it - whether in Japan or in America. Japanese people don't flip the order of the names Americans call themselves. We should extend them the same courtesy.
Indeed. It's really quite simple; we should call people as they call themselves, not how we think they should be called. It's the basic respect we expect for ourselves but the West is bizarrely inclined not to give to others. We come up with all sorts of systems, checks, and balances to decide what the order should be rather than just use the order that it is already in.
Why would you need to? You must've gotten the name from some source, just write it in the same order it is there - transliterating into a different writing system if necessary, but there's just no need to ever mess with the order.
