I was able to find at least 3 extant forks on Github, but the fact that the project author's employer was concerned about IP rights would make me wary about using such code. If the author "borrowed" similar code from work he previously did from the employer, it is likely that the MIT license of chart.js is invalid.
Odds are that it was a Disney-like situation: anything that you create while employed by Disney automatically becomes property of Disney.