My family converted a residential structure to commercial. We had to add fire protection, with sprinklers and additional exit doors. Fire protection requirements are significantly more stringent in commercial structures than residential. This wasn’t due to fire code.
Zoning allows it to operate as a church, where a lot more than a dozen people will be present. Zoning considered it safe enough to offer such services to the public.
He temporarily changed his operating hours from Sunday mornings to 24/7 for the duration of an emergency. There is no significantly greater risk from fire to these occupants than to the church’s regular congregants.
No, it might have very well met residential zoning requirements, even though it was not actually zoned residential. If it did not meet requirements, the most likely reason would be a lack of shower/bathtub, or a lack of closets or windows in spaces designated as “bedrooms”.
If he were offering housing under normal conditions, yes, there would be a problem. But he’s not. He’s offering shelter and respite - church services - at a church on an emergency basis.