You'll need to provide more information such as science GPA, overall GPA, state of residence, volunteer and shadowing hours, ECs and more. A TS of 19 and AA of 18 are a bit low, but there are a lot of other factors that come into play.
Average accepted is around 20. If he can get a high GPA, he can probably get a good score as well.
Shoot as high as possible and study with all that you have for 2 months.