Some parts /techniques are doable with acrylics, not so much the full wet on wet part of it. Unless you work very very fast..
I usually do layers of acrylic colors instead of the BR wet/wet.
One nice thing is , if you mess it up just let it dry and go over top of it.
But his brush use & techniques/style for greenery and scenery are pretty easy to catch on to.
I've used his style from PBS tv shows & youtube with water color & acrylics.
If she really wants to step up some notches skill wise she should look up the Jerry Yarnell website & his youtube vids. Also on some PBS stations.
Also the Partner: WetCanvas Live! section here is really good place to learn and see critiques & explanations.
http://www.wetcanvas.com/forums/forumdisplay.php?f=528