I'm sorry for your mom's condition. I am sure you're not surprised to hear me say that neither I nor anyone who claims to know the answer to your question can really say for sure what's to be. I think it would be irresponsible to give you numbers that are either false or would generate false hope. It sounds that she still has the capacity to be stimulated in some way and so even if bedridden I would recommend to keep up the company try and engage her in conversations and activities. Make sure she feels you holding her, squeezing the hands, the arms, touching the face. This type of sensory stimulation can actually be interpreted by the brain much more readily in demented patients more accurately than verbal stimulation. There is zero predictive ability between death in dementia patients and amount or type of vocalization. Get her out of the bed if possible and into the salon with the family and with friends. Don't allow her to become "bedridden." I find that to be an expectation of patients and families that comes from antiquated notions of feeling that the elderly and ill much prefer less activity as they age. Nothing can be further from the truth. Everybody wants to be active. Keep her safe that's true but don't allow her to stay in the bed if at all possible.