What instrument did Weaver play in Ghostbusters?

In the movie "Ghostbusters," the character Winston Zeddemore, played by Ernie Hudson, does not prominently feature an instrument; however, the Ghostbusters theme song features the use of a variety of instruments, including brass and synthesizers. The film's memorable score was composed by Elmer Bernstein, who incorporated various musical elements to create its iconic sound. If you meant a specific character named Weaver, please clarify!