[Boom Boom]

So sorry for your loss.
I spent many years as a mason and have rebuilt far too many chimneys due to a chimney fire.
Most chimneys constructed are crap, the liners are already cracked even before installed. If I had a common square type liner I would have a stainless liner installed inside if burning wood. Where I live I have easy access to hard coal and that is what I have burned for the past 20 years even though I have hundreds of acres of wood to my access. Zero chimney fire issues with coal.
The product you mentioned does work but you must be at home when the fire starts and most people are away when a chimney fire starts. Don't beat yourself up, odds are there was not much you could have done.
The last chimneys I built I used ductile iron water pipe, no way can a chimney fire make that fail.
For those of you that are burning wood, talk with your insurance company about installation of a one piece stainless liner for inside your clay liner. My brother-in-law only had to mention of risk of a chimney fire and he was offered to have a stainless liner installed at the insurance company dime.
Guess they were smart enough to realize spending a little now could save a lot in the future. Worth a call to your insurance agent.
Once again, so sorry for your loss.