Tell SS and SD that if they are ever home alone again past _____ (and fill in a reasonable, age-appropriate time here -- midnight? 1am?) -- that they can ALWAYS call you if they want to, and you will "either talk to them or come over."
Then, when they do contact you, GO OVER THERE and stay the night. When your wife asks you why you're there, tell her "Because SS was scared, and it's inappropriate for him to be home alone until _____"(fill in whatever time she finally traipses in). And if it ever happens again, not only will I come over again, but I will call protective services so fast your wayward little head will spin, and if you think I'm bluffing, you underestimate me -- again."
You don't "suggest" and you don't "send e-mails" when it comes to the security of the children. You DO.
Good lord, man, this is a no-brainer. The only "resources" this requires is BALLZ.
