Just so you know the Sim that has the issue is Wolfgang Wilder from the Werewolf expansion, so not a Sim I created but a pre-made townie that came with that expansion.
I mean I can try this, for fun and information. So he would no longer be married, and be the father of his child etc. My gallery username is the same as the one I use here.
It looks like the "new" Wolfgang is working. Although the freezing was a slow burn kind of thing, happening a little at first and then reaching the point of me sitting around for several minutes (real clock, not Sims) waiting for frozen household members to complete tasks. So I will play a bit more and see but for now the issue seems to be gone.
Of course this messes up milestones and family trees, and of course as you say, his relationships are gone. I can't decide if I prefer the freezing to new Wolfgang messing up all of that history. 🤔