... but on the occasion when Lilith died, she died in her sleep and by the time I realized it was too late.........
I didn't think that was possible -- I though sims had to be awake to die.
In an asylum challenge I played once, one of the inmates had a low hunger bar and also failure in energy. She collapsed in the dining room. The same thing happened to another inmate at the same time in a bedroom where my playable was sleeping. I was watching the bedroom, not the dining room. Grim showed up in the bedroom for the one, and she did wake up so she could properly die of starvation, but the playable did a successful plead for loved one interaction and she lived. However, upon checking the dining room, there was only an urn left, so I don't know what happened there. I suspect the sim woke up when Grim arrived and then was ushered out due to starvation. I suspect that sims probably wake up just long enough to meet Grim and die, but do not actually die while asleep. Bit of an academic point though.