As a legal resident without being a citizen, he can buy a gun, own a gun, in South Dakota open carry a gun, he can get a hunting permit, he can be a firearms dealer, he can buy and own machineguns and other NFA firearms, he had a SD CCW permit through multiple renewals, and now with a stroke of a pen that says US citizen he can no longer conceal carry. It is going to reverse, as nothing in firearms laws supports legal citizens from owning firearms.