Weed. The only thing that made my grandfather's life bearable (and even enjoyable). His tremor went away almost immediately (for the duration of the effect - 4-6 hours) and he could move swiftly and painlessly, even do some woodworking, brew his coffee, eat soup, and other tasks like that.

He consumed the THC extracted to alcohol shot (I guess some homemade spirit). The amount was low enough to not have any visible effect on his behavior.

One plant grown on their garden (legal where they lived) was enough for a whole year, and there were leftovers.