What schools offer generous merit aid

Unlikely. Merit aid is dangled like a carrot to entice students to attend a college they wouldn’t otherwise consider. Highly selective colleges have all the applicants they want; they don’t need to pay students to attend, so they don’t.

You can do a web search for “automatic scholarships SAT” to find colleges throughout the country that offer guaranteed merit aid. Assuming you live in CA, another option is to have your son attend a community college and take advantage of the guaranteed xfer to a UC (6 UCs participate). If he selects a CCC in the UCLA TAP program he also gets preference in admission, although given his academic strength he is likely to be a strong applicant no matter where he goes. For TAP see http://tap.ucla.edu/

You wrote you “live in a high cost state with most of our income going to mortgage” so it’s worth pointing out this is a matter of choice. You could move to a less expensive house and have more disposable income for the college years and beyond.