I take care of my 90 yr old mother with dementia. She is up at all hours and it is wearing me out. Why can't we get any medications to help?

Her Dr. won't give her anything to help. She is on zero medications for anything. I caused us trouble with Medicare because he said she was malnourished. We made him do a blood work up and tests that showed that everything was within normal limits. She is just skinny! Like I told him. He had to retract his diagnosis for Medicare. She is 5'3" and 102 lbs. I can't figure out why we can't get any medications to help with sleep and depression? Should I find a new doctor? She needs sleep and I do too!