Is the inability to communicate verbally a sign that end of life is near for advanced stage dementia patient?

My mother-in-law has dementia and her condition is progressing rapidly. I was her primary caregiver for 5 months until 3 weeks ago when she was moved to a memory care facility. She was diagnosed with dementia 18 months ago and continued to live alone for the first year. During the first year the family checked on her a couple of times a day and made sure all her needs were met. We made her meals and administered her medications. She used a walker but was very mobile. She could answer the phone, use the toilet, dress herself, etc...Her memory was deteriorating, but her speech was fine. The end of January she had an episode that resembled a stroke, but after a few days she was walking and talking again. There was a significant decline of her memory, however, and she needed 24/7 care. The family worked out a schedule so that she was never alone. She had 5 adult children who took turns staying overnight and I took care of her from 5:00 a.m. until 7:00 p.m. Her condition seemed to level out and she did good for a couple of months. She had a wonderful appetite and actually gained a few pounds. She was still mobile with the aid of her walker. She loved sitting and talking and looking at pictures. Her favorite thing was for me to put her in her wheelchair and go for a long walk, then come back and sit outside. All was good until she had another episode, again mimicking a stroke. She spent several days in the hospital and the doctors ran the gamete of tests. The neurologist said she never had a stroke, it was just the dementia accelerating. He said the episodes would become more frequent with shorter periods of plateauing. We took her to a geriatric specialist after the 2nd episode and he recommended hospice care. The family continued caring for her and a hospice nurse would come once a week unless we requested a visit. Within days after being put on hospice, she stopped sleeping. She went from sleeping 12 hours a night to staying awake for almost 3 days at a time. We tried the meds recommended by hospice, lorazepam then haloperidol. Neither worked and, in fact, had the opposite effect. She developed a pattern of being awake for 2 or 3 days until she would become so weak she would sleep for 2 days. After a couple of these cycles, she all but lost the ability to communicate verbally. At first she just had a hard time finding the correct words and putting sentences together. Now when she tries to speak there are no identifiable words. Almost overnight she lost the ability to talk, stand, walk, feed herself, or follow directions. During this time she also became extremely anxious, pulling on everything and constantly fidgeting. I believe there was more to her prognosis than we were told. The doctors never told us how long they thought she might have left. They did tell us that she did not have Alzheimer's dementia. Her dementia became apparent after she fell and hit her head. They said this type of dementia progresses much quicker than Alzheimer's. I understand that every dementia patient's symptoms are different, but if anyone could give some insight into what we might expect to happen in the near future it would be greatly appreciated. Is she in the end of life stage of dementia?