MIL in last stages of Alzheimer’s

I've been taking care of my MIL for almost a month now. She, I think, is pretty much in the last stages of Alzheimers. The hardest part for me is watching the "nothingness" of her days. She gets up in the morning and has "one" cup of coffee as she begins to work her "word search" puzzles. And, she works them all day long. She shuffles the pages and checks the answers and a lot of the time she doesn't seem to even be aware of anything around her. It is so hard watching this day after day. I wonder to myself how it must feel to have "nothing to do" or to not have anything meaningful to think about. At times she becomes sad about the situation she has found herself in and begins to cry, but most of the time she just sits and works her puzzles. I have tried other activities but she just doesn't seem interested in them. I do walk with her outside for short distances when the weather permits and I have bought several DVD's that I thought she might enjoy watching. So far, The Walton's seem to be the only show she will consistently pay attention to in the evenings. Other times when the TV is on she will work her puzzles or "pick" her finger nail cuticles. She just seems to be so "unaware" of those around her. Today I was wrapping Christmas gifts and again tried turning the Christmas music very loud to see if she would stop her puzzle working and listen to the music. It didn't work. What is in her head? What is she thinking about? I don't know how to make her days more meaningful. I don't really know if this is a desire I want for her or for me. It is just so hard watching her do "nothing" all day, go to bed at 9:00 PM and get up start the "nothing" all over again. Any suggestions anyone????
Susie

Thanks Steve for the advice. Sorry your dad is so difficult at times. I do remember when my dad would do things that were dangerous before he got worse and couldn't speak or eat. He was upset because he thought the newspaper carrier was charging him too much. He called the newspaper office and was very ugly to them. I had to call them and explain. He was being charged for two separate newspapers from two separate companies. He was upset with his son and grandson that was living in the house and many times I had to go over there and try to "reason" with him.