OMG triplets!!! That's pretty much in a the deep end! Wish her (and you) luck.

I have had reactive hypoglycaemia, am now insulin resistant and borderline diabetic too, and like you it runs in my family.
I also have (had?) severe blood sugar lows.

I can't do CAD, the carbs knock my insulin around too much.

I did Atkins induction (felt a bit ropey, but got the insulin sorted out quickly) and then onto Protein Power, but could have stayed on Atkins. I eat 5 or 6 mini meals a day, rather than 3 big ones.

When my blood sugar drops or I'm hungry I eat, but nothing with any appreciable carbs in - ie I couldn't handle raisins.

I make almond muffins (recipe in kitchen section) and carry these at work - these saved me, especially in induction (not strictly allowed, but hey, I had to survive).
I also carry brazil nuts and fill the work fridge full of chicken drumsticks, eggs and salad. Occasionally I need to eat every half an hour. This only happens rarely these days, though it happened more at the start.

Basically, my blood sugar is now miles more stable than it has been for 20 years.

Oh - and I avoid all caffeine, it also messes my insulin up and gives me hypos.

I don't buy lowcarb food, except Splenda, partly cos of the cost, partly because its rarely available here and partly cos some of it seems to be full of rubbishy 'non-food' anyway. So, I eat quite plainly, apart from the odd recipe from this forum for sweet treats of one sort or another.

Hope some of this is helpful, take care, Jay