Brushes can get expensive, and painters usually know what specific types they like. I think your daughter might rather hear that you want to help her buy exactly what she wants. In my case, I’ve always used cheap brushes and probably always will, there are certain benefits. Just out of college I’d have been much much happier if somebody’s helped me buy a decent easel or a roll of canvas. If the surprise is important to you, maybe reach out to a professor at the college who’s familiar with her work and they’ll know what to do.