The stated intent to make sure babysitters can use deadly force to protect themselves- basically, allowing the Castle Doctrine to apply to them even if they aren’t in their own home- I think is fine.
But either some incompetence happened or that was just cover for the crazy. It really hinges on “specific authority”, which sort of sounds like you might need more than mere permission to be present before you are covered, but it’s unclear exactly what you need. The broadest interpretation makes this incomprehensibly worse than Stand Your Ground- not only eliminating the duty to flee entirely, but vastly reducing the threat someone needs to pose before you can kill them.
No one should be forced to choose between suicide by asshole and prison, so looking at self defense law to see if there are situations where duty to flee is too strong, or the bar to opening fire is set too high, is reasonable. But simply throwing that shit out entirely like this is idiotic and immoral.