The animation played, and the mom died and left behind an urn, turning into a ghost.
I used master controller to make her die from electrocution, no problem. I already got rid of the mom (young adult). So I created a sims family based on a story idea I have.
I have a number of mods (MC, 'Deadly spells' mod, a 'fairy' mod, a 'death angel' mod, some height slider mods, etc.) and custom content but honestly I've never experienced this problem before and all the mods are up to date as is my game.