Suggest Remedy For Severe Dementia With Psychosis

Question : my mom who is 90 years old has been using Combigan for glaucoma for several years. In the last year she has developed dementia with psychosis. Her psychosis is mainly that she looks at my Dad on some days and does not recognize him. She never really ever recognizes him but she has accepted some of the "substitutes", meaning she sees him some days as a good guy, but not her husband ever. When she sees him a a bad guy, she is scared all day, hiding out wherever she can find a place in the house and crying a lot. I feel the psychosis is real but I believe it is brought on by several things, one of them being poor vision. She just can't see him properly and panics. We have asked the eye doctor if we can use something different than Combigan for her glaucoma and he said no. We have read that the use of Combigan can actually cause hallucinations so we are very concerned that although this drug is useful for her glaucoma, can it actually be causing these episodes.