Concerned about my mom (90) with advanced Alzheimer's. Does anyone have a similar situation?

Hello. My 90 year old mom was diagnosed with Alzheimer's a little over 7 years ago. She is at home with 24/7 care, is bedridden due to a broken hip last year. She wears diapers and is totally dependent on others for care. She is capable of saying up to 6 to 7 words but mostly she mumbles and can not communicate. My concern is my brother, who is her guardian and lives with her, is in denial about how severe she is. He believes she is doing great, even improving. She sleeps around 17 hours a day now. Even though she can hold her head up, we notice a little difficulty beginning to develop in that area. She still eats well but my brother wakes her up in the morning before she is ready, and as soon as she is fed by an aide, she is back to sleep from maybe like 11 to 3. Anyone have a similar situation or does anyone know anyone with similar symptoms? Can't get a straight answer from my brother.