What can I do if my mom is growing thinner and thinner as the years go by?

Mom has Alzheimer's, had ischemic heart attack twice for the past 10 years. Lost much of her teeth and appetite, loves to sleep, is 79 years old, has incontinence 24/7 and had hip replacement surgery last 2009. Walks very slowly, chokes occasionally while eating, do sundowning maybe 3-4 times a week, has memory loss, and coughs especially in the morning and when eating while attempting to talk or make herself coherent. But I pity her watching her really become thinner and her frame shorter due to osteoporosis. She has no cancer, no diabetes, just erratic blood pressure, Alzheimer's, incontinence, arthritis, osteoporosis, vertigo, bad hearing but very clear eyesight but very terrible short--term memory. She is getting thinner and thinner as years pass by. I saw this happened with my grandfather who had lung issues and was a smoker when he was still young & strong but quit smoking when he reached 60. It's pitiful to see mom become almost a skeleton. We often feel embarrassed to bring her outside of the village as people stare at her like she's a skeleton from the tomb. Please share your thoughts and advice. thanks very much