Test score is holding him back from a lot of opportunities so first and foremost my suggestion is to get that up. A few hours of prep could get him tens of thousands more.
After that and after targeted applications to automatic merit/competitive merit/and reaches are done, do your typical round of highly competitive outside scholarships. Coke, GE-Reagan, Buick, Burger King, AXA, Jack Kent Cooke especially – all look well upon students who have accomplished a lot with very little.