There is a mod that makes royalties inheritable if the sim earning the royalties dies. (Might even be a feature of MCCC...don't recall).
Beyond that, my understanding is you don't 'lose' the royalties just because you are playing another household, they just freeze...so if you had 2 weeks of royalties left, and then played a different active household for 2 weeks, the sim who had the 2 weeks of royalties will still have 2 weeks of royalties left if you go back to actively playing them.
I don't know this from personal experience, but I'm pretty sure I've seen someone explain it that way here in the forums. Based on what others here have said, sounds like it is glitchy though if that's how it is supposed to work.