Yes-I've seen treadmills with a negative incline setting, but I agreee that it willl be difficult to really get good downhill training that way. Downhills were my main problem when I moved from mainly tready running to the "real world"
Having said that, when the "weather bomb" was going off last week, I did a good (up)hill session on the tready. This week it was just ordinary rain, so I went up the local hills instead. The "real thing" is much better when it is feasible, but the tready is better than sitting on your arse.
The problem she is having with (probable) low blood sugar levels is NOT a common symptom of undiagnosed diabetes- hypoglycaemia is more common in treated diabetics ( as a complication of treatment).
A random blood sugar test is not all that likely to help- a test during the symptoms would clarify the sugar level when feeling unwell, a fasting blood sugar test is better for excuding diabetes, but I DO NOT think that is the cause of these episodes ( I 've had exactly the same, and as I'm a hospital Dr. I've checked my BM during them, and it's usually about 4 !).
I agree with RicF- it is most likely that the attempts to push your sugar levels up are contibuting-the "rebound" effect after taking simple carbs is your problem whilst running.
I had a similar problem, a few years ago, it has got better with marathon trainig, as I'm used to running on empty most mornings, so am better at fat- burning. It might just get better if you get used to running without eating just beforehand, and not taking any carbs on board unless you are out for more than 90mins. Just plain water.
Sorry, but you've been asking about a series of hip injuries for over a year. Have you been to a physio/ got any advice from a professional? Trying to sort this out by asking on the interweb isn't goingto get this sorted, unless you can identify with confidence what the problem is, and sort yourself out with a series of appropriate excercises to correct the problem.
Seriously- can't you get advice from a local sports injury clinic?