At this point I reckon that you’ve done a damn sight more than is strictly required, so the coulda and shoulda sort of guilt is not operating. The woulda sort of guilt - well, she’s your Mum and you love her. In spite of all the current difficulties.
Imo, and this is strictly my own opinion, is that one of her current hungers is for agency. The question is, does that hunger hit harder than physical food hunger - and imo it currently does. And independent agency is contraindicated due to other factors.
You’re battling a shit storm rn, and there are no good or right answers. All you can do is the best you can in the circumstances, and try to sleep at night. Feel for you.