When you say your Mum was "required" to take medication after a previous admission, what do you mean by that? Was she under a CTO? I can't see what country you're from so I'm speaking from a UK perspective here. If you can please let us know that would be helpful, we really can't give much practical advice otherwise since you've already said she won't go see a doctor!

As other commenters have said, it's likely your Mum has schizophrenia. The delusions she's having are very typical and her previous diagnosis of bipolar disorder may need to be revisited. Episodes of mania and psychosis can have very similar symptoms.

Your Mum saw a psychiatrist very recently when she was in hospital. At that time they would have checked to see if she met the criteria for detention. In the UK she would have likely been held under an emergency treatment order in this time, which lasts 72 hours. They would have been assessing her for the next step up, a short term detention order. Although their assessment led them to conclude she didn't meet the criteria at that time, it's perfectly possible your Mum wasn't completely honest with the doctors, although she clearly spoke about her delusions. Did you or another family member give a collaborative history? If not, you could go back to that psychiatrist and speak to them. They are allowed to speak to you to gather information about your Mum even without her permission, as long as they don't tell you any confidential information and it's purely you giving them information. They won't get her to 'tell them she's suicidal' as has been suggested elsewhere in this thread, but if she's at risk of harming herself because she isn't eating/taking care of herself then this is enough to fulfil the criteria in the UK for being at risk of causing harm to herself.

If you don't want to make your location public but want more info on UK stuff, feel free to PM. If anyone knows US or wherever equivalents please comment. I'd be interested to know how it works elsewhere & it might help OP!