Sure man, we can talk. I get acupuncture ~1-2x/week regularly, a combination of body points and a specialized system of scalp acupuncture called YNSA. Almost immediately after the scalp points go in it feels like a little rush of blood to my legs and the day of and 2-3days following I can notice a difference in the smoothness of my gate (leg/walking movement). Usually get points in my lower back and along the spastic muscles (inner thigh, calves). my feet drag from the rigidity so usually get points to help that. Sometimes some in my abdomen to release muscles of the hip to help lift my legs. Because of my legs getting weaker and starting to atrophy I was expected to be in a wheelchair by the time I was 20 - gonna turn 29 in a couple weeks and feeling stronger and more able now than then. Still have trouble with things like I'm kinda slow and awkward going down stairs... It's helped me a lot tho and I have seen other people who have had a stroke and can barely walk get just several scalp points and you can see a difference in strength and balance.
I do that a lot with regular exercise - leg muscles are weak and want to avoid atrophy-, an herbal formula from my acupuncturist that helps, Carnitine, B vitamins and Magnesium (for muscle spasms). Happy to answer any questions you've got. Does that still sound similar to yours? If so, I think it would definitely be worth trying, just know if you've had it for a while it might take a few treatments before you see effects.
I empathize with your circumstances. There are a lot of blanks in your story that I am going to try to take an educated guess at filling in those blanks. You stated that your sister has appropriate behavior when she is with…"