According to this: https://blog.ipleaders.in/star-wars-is-owned-by-disney-walt-...

Disney bought the operating businesses of Star Wars, Indiana Jones, and Lucasfilm in live-action film production, consumer items, video games, animation, visual effects, and audio post-production as part of the agreement. Disney also bought Lucasfilm’s entertainment technology portfolio.

If this author’s work wasn’t part of that buy…I’m not sure why Disney would be on the hook for the royalties.