Being harassed by a narcissistic LBD grandmother who is making false accusations. What are my options?

My 82yo grandmother (likely) has LBD and is a narcissist. Her and her husband both live in a skilled nursing facility as they are unable to care for themselves. His dementia is more mild than hers. His primary symptom is a short memory span with no behavioral changes but she has severe hallucinations and delusions in addition to having memory issues. She also has a history of lying (and has for her whole life), so we have trouble deciphering when she is telling the truth. Recently, she told my entire family and the nursing staff that her husband is the reason why she has frequent falls. She blamed him, saying that he pushes her, and said that the bruises on her arms are because of him. It is likely that the bruises on her arms are from him, because when she falls and tells him to help her, he grabs her arms and tries to pull. He is 92 and is not strong enough to lift her, so he just pulls harder, causing bruises. However, he does not push her. She made it sound as if he was abusive, hence why the staff separated them. We have told them countless times to call a nurse for help rather than relying on him, but neither one listens. They also fight constantly because she is always yelling at him. This prompted the staff to move her to a different room.

All hell broke loose when they moved her. She has been screaming nonstop, calling us at work, saying that they won't let her see her husband (not true) they are abusing her (not true) and that we are abusing her (not true) and stealing her money (also not true). It is clear that she is doing worse away from her husband, but he is actually doing much better. She always starts fights with him and stressed him out but without her around he's very calm and clearly much happier. So question #1, should we do what's best for her or him? Keep them apart for his sake, or put them back together to get her to stop screaming?

Question #2, Is this behavior common with people who have LBD? The constant lying, delusions, accusations, and overall difficult personality? Is there a medication that can help keep her calm? She's already on Xanax 3x a day. She swears that we are stealing her money, but their money is being used to pay for their care. I know that you can't rationalize with people who are delusional but how are we supposed to just sit there while she screams in our faces that we're stealing from her and mistreating her, and that she's disowning us? My family has dropped everything to care for these people, and to be treated like this in return is infuriating.

The nursing home is debating whether they should send her to a psychiatric hospital because of these issues. She has been at this hospital before because she threatened to kill herself, and she demanded that she never be sent back there.

I am so frustrated and angry with this woman. I don't know what else we can do at this point. My family is tired of dealing with her constant accusations and difficult behavior. I guess reducing our visits is the only option to protect ourselves from her harassment. I'd like to know if anyone else has dealt with behavior like this and can offer any insight.