The only thing that satisfies a workaholic is doing actual work, so no, cleaning house or raising a skill won't do it. However, I don't think you'll see any negative effects from the trait as long as the sim does do some actual work, maybe a few times a week. He might roll some work-related wishes he can't fulfill, such as working overtime, but you obviously don't need to keep those.
On the other hand, it sounds like you might enjoy having this sim in a rabbithole career so you can focus on your main sim while he's at work.