That mercaptan is NASTY smelling stuff. It’s pretty amazing you can’t smell it.
Great thinking on your part to protect everyone. I’m glad it all ended so well for you.
I don’t know for sure, but I think these days you can buy alarms that alert for gas. They do for almost everything else.
I think the Carbon Monoxide alarms work for that.
I only smell a few things and some are not strong smells at all. Wife has a hound dog nose. Had she been home back then it would not have been close like that.