Mom is turning into a tattletale, that is NOT telling the truth! Has anyone else experienced this?

Does anyone have this new problem that we have developed in our household?
Mom never talks, but in the past few days she has been up and about the house and nosing into everything. I am always around and hardly ever out of her sight, and if I am in and out, I am always checking on her. There are things to be done outside, but I can't drag her in and out of the house by myself. As if I don't have enough to deal with Mom, our son-in-law has decided to turn into a different person and run around on our daughter. We feel this is none of Mom's business and she would just set around and dwell on it, if she knew what was going on or could even remember (we are beginning to question just what she does remember these past few days).
Yesterday, our daughter had an appointment with an attorney and asked me to go with her. I did! I told my husband that I did not have this child to let her stand alone at a time like this, just because Mom doesn't want me out of her sight! It took a little longer than expected and when my husband came home from work, my Mom greeted my husband with, "Hello, have you seen that wife of yours anywhere. She's been gone all day!" I called and told him we were running late and I could tell from his tone, that things weren't going to well. I was in and out of the house until almost noon and home all morning. I did disappear to take a bath and do my hair and of course, that was out of her sight!
I told my husband, that could really create problems by her telling him I was gone all day, (he knew better, cause he always knows my whereabouts), especially with how our son-in-law is doing our daughter. That could put a question of doubt in my husband's mind, that I might be out running around with her saying something like she did.
She has went from not talking and sleeping all the time and not eating and setting in her chair all day or being in bed, to talking too much and saying stuff she needs to keep her nose out of, to rambling and staggering around the house and could fall at any time. From sleeping all day into the evening to up at the crack of dawn and just barely being able to get her to bed at night. From not eating a thing only Ensure and pudding, to eating everything there is and swearing she is not hungry! Has anyone else experienced this "about face" action and the tattletale stage? We are just clueless as to what is going on with her and really questioning her dementia. My husband says he thinks she remembers more than what she is letting on. Is she just playing us? Any, help and info would be greatly appreciated. I am wit's end and am just about to go bonkers myself! Thanks in advance!!