I am nearly 4 years after diagnosis. I had sleep problems about 2 years back which was due to right arm stiffness. After some search I sarted taking magnesium, melatonin and velarion root before sleep which I found helpful and I continue taking them up to now.
But what was more helpful: exercise. I do 45 mins twice a day ..very strict regime of yoga, taichi and home padelling. This almost solved the stiffness problem which in turn made my sleep much better.
I still have the annoying tremor! most difficult to resolve
I wish your friend sound sleep
Imad