My grandmother has frequent hallucinations that she is falling

[mooninscorpio]

My grandmother is 79 and her health has been going from bad to worse within the last half year. She had stopped excersizing due to a bad knee and was scheduled in for a knee replacement when she got, what she thought, was the flu. They went ahead and had the knee replacement done, but she never really managed to do a lot of rehabilitation of the knee because she had this persisent flu. The flu was paired with a loss of touch and the feeling of numbness in her left side of her face. This sensation of numbness never disappeared and she still has this to this day. This feeling of the flu also never left, some days were better than others, but she continued feeling weak and started losing weight extremely quickly. But now she is having frequent and alarming episodes (a few times a day that last around 30 minutes) including hallucinations. First she thought she only had these episodes in her sleep, but now she has them during the day as well.
She describes it as feeling a band or a rope tightening around her head and hearing a very loud mechanic/machine-like sound and then she thinks that she's falling down a very high flight of stairs, sometimes even taking her loved ones and family down with her. When she is having these episodes her eyes are closed and she's completely cramped up, sometimes screaming and at some point hyper-ventilating. We're not able to get through to her when this is happening. She has been to doctors and hospitals many times in the last half year. She's had MRI scans and epidurals and the doctors have confirmed that she has had a TIA at some point in her life, but say that this has nothing to do with the TIA. They definitely think it is brain-related. They think they see some activity through the MRI scans in her neck area, but do not think that it is cancer. Any tips or ideas are welcome. Also tips that would relieve her of some of the stress and agony she is going through. The doctors are hesitant in doing any treatment because they do not know what the cause of the symptoms are (yet).