Reoccurring hallucinations with dementia and sudden vision loss?

My mother has dementia and has been legally blind since March when she had another stroke to her optic nerves . Her confusion has gotten much worse and she is hallucinating. It is the same hallucination that a young man named Robbie is in her room, writing graffiti on her walls, trashing her stuff, and leaving her nasty notes. Everyone shows her that there is nothing wrong and no graffiti but Mom is still convinced this is happening. She is so stressed out every time I talk to her on the phone and visit her. She begs me to bring her home to live with me. The staff at the memory care unit take very good care of her and I know she needs a lot of care 24/7. Psychiatrist is trying new medications to see if it helps. Has anyone else experienced this with their loved one who has dementia who had sudden vision loss?