My mom is a brittle diabetic and was in the trials for the first insulin pumps way back when. (1970's)
+1 on the high protien/complex carbs diet. Mom ate that way before the docs started recommending it, and it really helped.
+1 on carefully watching what happens during exercise.
Also, consider the insulin. Different folks need different insulins. Beef and pork insulin lost effectiveness for my mom just as Humulin came along, which saved her butt.
Is it possible her pancreas is making some insulin of its own? (Mom's is completely dead, so I don't know what that would look like.)
Will your insurance pay for her to go to a diabetes specialist? Unstable diabetes can wreak havoc, and if it goes on you will see effects for years.
Mom's insurance is pretty bad, she goes to Canada for some of her supplies (even paying full price there is cheaper than her co-pay here) and gets her pump sets on eBay.
(I won't give my political opinion on the state of US healthcare when someone gets medical supplies necessary to live off eBay because it's cheaper than buying them with insurance at the pharmacy.)
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson