Hmmm... well definitely the less she eats of the crackers, sugars and stuff and more good fats, the less she will be affected by hypoglycemic symptoms.
As for the migrains, it will probably help to eat better foods and eliminate the bad stuff, but without more info it's hard to see what may or may not be causing them.
I'd suggest maybe just figuring out some foods that she likes that are Primal and havng those around more often. If good stuff is there and she actually likes it, she may lean that way more often. Maybe make veggie chips to have with french onion dip, pumpkin muffins, coconut flour pancakes, eggs and sweet potato fries for breakfasts... just some suggestions, but you get my drift.
Other than that though, you really can't make someone change. There's been a lot of threads about spouses, and the ones I've seen that were successful were where the Primal spouse didn't try to change the other person at all, didn't talk about it all of the time and didn't try to "convince" them. They just provided really great food for meals, did their own thing and the spouse noticed the changes, or liked the meals and slowly started to drop the bad stuff, or ask questions. She may (or may not) do this, but truly it's her decision. Some people though will respond badly if they think they're being pushed into something they don't want, and may resist just because of the way it's being handled.
Just some thoughts...