I am sorry to hear about your sister, and do not know much about a spinal fluid leak, but I may be able to help with the thyroid issue.

The loss of hair could be from the thyroid. I was recently diagnosed with a nodule on my thyroid (found in my pre-op physical before my spine surgery), and had to get blood tests, a thyroid ultrasound, and then a thyroid scan. I have to do it again, 3 months after the 1st tests. Has she had this checked out? Some of her other symptoms could be thyroid related.
She needs to find out if her nodule is functioning with the thyroid, and if it is cold, warm, or hot.
And, sometimes, they biopsy the nodules. My nodule is hot, so no biopsy, yet!
And, she should have a blood test, to determine if she is producing enough of the thyroid hormone, TSH. If this gets too low, it can cause the hair to dry out and fall out, lack of energy and total fatigue, depression, appitite changes, etc. If she has too much (they can go both ways) it can cause weight loss, amoungst other things.
Three of my closest friends have thyroid problems, and they have all shared their info with me.
I hope some others can help with the spinal leak. Keep us posted as to her progress!
Carolyn