The best scholarships come from the colleges and are either based on need (income) as determined by the college or merit (SAT/ACT + unweighted GPA). They aren’t awarded for individual accomplishments. Spend some time reading the financial aid forum to get a better idea of how it works.
You can run the FAFSA4caster to get an idea of what your EFC will be. If it’s low enough, your son will qualify for a federal Pell grant of up to ~$5k/year. The FAFSA EFC has no bearing on the parent contribution calculated by the colleges. Those numbers can be very different. He can also take the federal student loan (~$5500/year). Any other grants will come from the schools.
You can also run a couple Net Price Calculators (each school has one on its website) to get an estimate of what the college would cost if your son was enrolling next year. You may have to play with test scores and GPA to see what scores would qualify your son for merit aid, but I think you can get a rough idea of out-of-pocket costs.