Is your student a NMSF? If so, there are many schools, most notably UF and USC, that offer major merit scholarships.
If not, most merit scholarships, especially those at already selective undergrads, are extremely holistic: after meeting a certain academic requirement, they’re looking for students who fit the sponsor’s interests, whether a certain major, leadership qualities etc. Check each school’s website that your student’s interested in for more information on their review processes.
Hope that helps!