By all means, have him take it/them again. However, a higher score will not help nearly as much as most people think. A higher ACT/SAT is more likely to get him more academic money at a private school than a large public university. A higher GPA will probably help more than a highter SAT/ACT. But, shoot for both anyway.
Again, I would still retake the test(s), but I wouldn't count the money just yet. Also, be leery of baseball coaches who tell you "that score/GPA will probably get him tons of academic money." They're just guessing. Unless/until you have it in writing from the financial aid office, assume nothing. When GPA's and test scores start getting really high, some coaches will use that as an excuse to make a lower athletic offer. Kids shouldn't be penalized for high academics, but it does happen.