Will my mother continue to decline?

My 92 year old mother has experienced a sudden and rather sharp decline (within a period of two months) in lower extremity mobility resulting in falling? She has increasing dementia. Twice hospitalized in this time span, first for a severe headache, then 2 weeks later for syncope, she returned to her assisted living facility upon release with a walker which helped initially, but she is now often unsteady on her feet, wobbling and falling even with the walker. Her gait has slowed significantly. It is a shocking 180 degree turnaround from her previous physical agility and, although her cognition has declined as well, it does not seem as dramatic as the physical. She is a pack a day smoker and is unable to give up her cigarettes. Is this rapid decline likely to accelerate and lead to her confinement in a wheelchair? She is on aricept. Many skilled nursing facilities are smoke free, making the prospect of finding a suitable placement in the future very daunting.