Good auto merit aid can be found at the following (as in, it’s clearly shown on their website and you can calculate based on your stats). I’ve also put in some stand out programs that might perk your interest.
Arizona
Arizona State (Barrett honors / business school quite good)
Alabama - flagship (good for engineering / Randall Research Scholars / Blount Liberal Arts Scholars)
Alabama - Huntsville (good for STEM)
Ole Miss - great honors college / Croft Institute for international affairs
New Mexico
Miami OH
Good merit but have to apply / more competitive is available at South Carolina with the best honors college in the nation?? / Capstone Scholars
There are lots of places that offer merit but it’s not advertised extensively, or you need to apply, or it’s competitive. The thread @thumper1 highlighted above will have extensive ideas and info.
It might be an idea to apply to one or two auto merit places that your son is interested in (even if not madly in love with), so that at least you have a couple of solid safety choices. The applications often are not that long - the Alabama famously takes 5 mins 
(Honors and other programs are a separate app, but you’ll know pretty quick if you’re accepted and with what $$)