Mom was taken out of senior living a month ago, now it is locked down. Can they still charge her and make her give an additional 30d notice?

The assisted facility isn’t going to hold her room for free. As long as her belongings occupy the room, she has to pay. If her contract also requires a notice period, she has to pay.

Look over the contract you signed when she first moved in. If you want to hold her apartment while she's not physically there, I imagine you'd have to continue paying, but I don't know if that even makes sense, since this situation can wind up going on for a year or more, who knows? Just because they're in lockdown mode now, they are still operational, right? As far as 30 days notice is concerned, I'm sure you'd be on the hook for that no matter what........it should be clearly stated in the residential agreement that was signed originally. No use asking us...........see what your mother or her POA agreed to originally. My mother's is in a binder here in my hanging files.