Sorry, never had any cooking classes or worked as a chef.
My snobby brother does do some writing on cooking; and I cook quite regularly for quite a few people. So I can't offer any useful advice, beyond the usual snobbery:
What I do, is select an area I want to gain expertise in (grilling was one of the first, obviously), read up a bit on it, and practice, practice, practice. After each meal, I assess what went right, and what went wrong, and how to improve for the next time.
You've got to mix study with practice in the field; because you can read all you want about marbling on a steak, for example, but you're not going to really "get it", until you slap a couple on the grill, and observe the different results. With experience under your belt, you can go back and appreciate some of the finer points (or spot the outright BS, like some pompous bellybutton talking about "The spirit of the steak").
So I can't offer much practical advice here; but I'd recommend this:
First, what does she exactly want to learn? Cooking is a huge field; what sorts of dishes is she looking to prepare?
Second, before spending money on a cooking school, invest in a good kitchen reference work. Believe it or not, I find the third edition of the "Joy of Cooking" very handy -- it doesn't contain merely recipes, but detailed descriptions of A) What to look for in foods (which ones are good/ripe/quality) B) how to prepare them (someone drops a duck on your doorstep and you've got to carve it up) C) detailed descriptions of physical and chemical processes. It's a great starting place for the basic "how tos" of cooking, explaining what happens and why. Of course, other texts can be useful -- but this depends on their style. For me, a good cook book doesn't necessarily have pretty pictures or fancy recipes: just good techniques, technical discussion and artistic crap.
Third, before going to classes, try to cook some in the style to be studied: basic instruction and advanced training cost the same, but one can be done at home.
Fourth, don't listen to people like my brother who might write fancy articles for fancy magazines. Don't listen to me either.
Fifth, quality ingredients and simple preparation are 95% of what you need. A good steak requires very little to make it great.
And remember, eat your mistakes

So sorry I can't be much more help.