It's interesting that your sister has MS. I was reluctant to throw this out when I first read your post because I don't know anything about ALS, but I wonder why doctors and medical researchers always seem to have a preconceived notion that a virus may be involved with respect to a disease, but never a fungus. Here is a website of a woman and author who took the approach that MS could be caused by a fungus and cured herself of the disease. If you click the link on the side to the author's biography, you can read more about her background with MS:
I wonder if the same could be true of ALS, that is, that a fungus may be involved instead of a virus. It seems that doctors and medical researchers limit themselves by not at least considering fungus as a possible cause.