I thought the business visitor case might not apply because he was hoping to move for several years, but it might be worth looking into the conditions for renew

I thought the business visitor case might not apply because he was hoping to move for several years, but it might be worth looking into the conditions for renewal (though 5 renewals might be pushing his luck). The wording on the NAFTA bit doesn't help as much as you might hope, though; GP doesn't match any of the long-term categories so his main sticking point is the 6-month maximum for business visitors.