How to stop my mom from sitting up in bed (sleepwalking) all night long?

My mom is 77 years old & is a 22 year cancer survivor. In recent years she's been battling COPD (chronic coughs and some bouts of bronchitis) and congestive heart failure. Most recently she's starting with short term memory loss and dementia. We have 24/7 private in-home aides because she can't be alone anymore. She's on several meds but I believe she's been a sleepwalker for many years. She's lived alone for 18 years since my father died. Nobody knew how poorly she sleeps. We've learned that she sits up in bed every night, several times. Sometimes she'll get up and go to the bathroom or walk into another room, but most of the time she sits up in bed and sleeps that way. We're worried she will fall and get hurt. The aides don't get a lot of sleep because they're always trying to get her to lay back down. Any suggestions to help break her of this sleepwalking/sitting up in bed?? Has anyone tried hypnosis for this? Thank you!