

Ive never heard of carbon brushes referred to as coal. Is it a language thing? They are made out graphite, which is also mined, but its different enough from say https://en.wikipedia.org/wiki/Anthracite. I think graphite is actually closer to diamond than it is to coal, in terms of chemical makeup.
The Fischer King came out a decade earlier, let along Awakenings, Goodwill Hunting… even Good Morning Vietnam was overall a very serious movie.