I seem to recall your symptoms add up to a particular disorder, but I do not recall what it is at the moment. I'll look it up for you in a later post. But I wanted to at least tell you that if anything is disrupting your sleep, or if you are not getting enough vitamins and minerals, or you are not staying well-hydrated, you can get your symptoms, so doublecheck all that stuff for now. I'm out of time and will get back to you.
I'm back, yesterday our computer server went down in our area, I was on long-distance. The itching hands made me think of kidneys, looked thru my book and found, if it's not what your sister has, it's possible you have some form of diabetes. I know you've had blood tests, but that was what I wanted to tell you yesterday. Until they test you for your sister's disease, some general "bandaids" are to get some plain saline drops for your eyes, exercise so you will rest well, and eat lots of Vitamin A and C foods, helps mucous membranes, and so does plenty of water. I assume you've talked to your sister, you can look up online what herbs are good for her disease and try those in a tea, perhaps, too.