It would probably be easiest for him to hire an English-speaking person as a cofounder or early employee for copywriting or communication, I guess.
There were other requirements for the cofounder, you know it's not easy to find the right one. I took English knowledge into account (also tried to have a native speaker as a cofounder) but it was just one out of several parameters with some weight.
Regarding the early employee option suggestion, so I should take that into account when estimating the size of a needed seed funding.
Just find someone who speaks it well enough, it's not really even that big a problem. A good chunk of the world's population speaks English natively!