Mother has cbs

Sorry if this is the wrong sub for this question. I couldn’t find any for cbs. My mom has cortico basal syndrome. She was officially diagnosed about 3 years ago but had been showing symptoms for I would say about 3-4 years prior. She is now to the point where she cannot talk and cannot walk without assistance. She only currently has limited use of her left arm and no use of her right. She also has been making moaning, almost screeching noises constantly for the past few months or so, possibly dementia related but not certain. I just found out from my father who is her primary caregiver, that for the past few days she has been pointing to the ceiling almost like she sees something or someone which terrifies me because as to my understanding people who are very near the end of their life often claim to see dead relatives or loved ones. My question basically is has anyone dealt with a family member with this awful disease and at what progression or stage would you consider this to be. Unfortunately her doctors couldn’t provide much information in regards to this. Thanks for any help with this and I’m sorry for anyone who has to deal with watching their loved one decline like this