Hi Mick,
Your having it tough, and i do sympathise. I as a parent of a 10yr boy have very few problems yet! i can only imagine the frustration of watching your daughter fading away. She does need specialist help, with a good dietician, her DN, main diabetic consultant and perhaps even a phyciatrist. Diabetes is a tough game to follow, but injecting insulin she must. It's like fueling a car, she needs to put the right nutriants into her growing body and the correct dosage of insulin. On 4 injections a day, i would assume she is having a basal, and bolus before/after food. She needs help to get the balance right, to learn to carb count and inject accordingly, done correctly she will not gain extra weight.
If she continues to do this, she is at risk of stopping her periods, growth will be affected and the risk of osteoparosis is greater in later life. Sorry if i've been harsh, i do not wish to sound as if i'm lecturing you, but i have seen a teenager go through this and the end result was heartbreaking.
If you can give us an idea of her insulin, daily diet and regime, we'll try and be as helpful as possible.
Regards,
Suzi x