Well, we're not doctors here, so no diagnosis can be given.

But, in my opinion something is going on for sure with your mom. It could be mental illness. It does sound like psychosis to me. However, that can come from a lot of things. And, it would be very good for her to get a fully body check to rule out any physical illness like you say. It could be many different things from schizophrenia or psychosis disorder, bipolar or depression has some psychotic features at times, or even things like dementia or alzheimers can have similar effects....

One thing with mental illness is something called "lack of insight" in which the person suffering the psychosis is incapable of realizing what it is. Learning to determine delusions or even hallucinations is called reality checking, and it's a very difficult skill to learn.

You talk about not speaking English and a different culture, so I don't know if you're in your home country or another county. But if you're in the US you can't do an involuntary stay at a hospital unless your mom is a threat to herself or others. So the question is if she is plotting to do anything to your neighbors or just complains. You say you worry she will get into a physical altercation. Call the hospital and tell them that is your concern and see what they say.

I wish I had better advice, but getting help for mental health when it's not wanted by the patient is almost impossible.