Any tips to prevent someone from leaning to one side?

My grandma has dementia and has been leaning to one side for a long time but lately I've been noticing it more frequently and its' getting harder to manage. I know it's called Pisa Syndrome. The doctor is aware she has this and in fact suggested I have a shoe lift created to help with her walking. She goes there in two weeks so I figured I'd talk to her foot doctor about it. But this has to do with being supported in her lift chair. I have been rolling up pillows to give her more support but even then the pillows aren't strong enough to hold her upright so she ends up falling over. I'm not worried about her falling out of the chair or anything but it's uncomfortable for her. She complains her arm gets so sore from holding herself up and she broke her neck a few years ago. It never quite healed without pain so now when she leans it makes her neck have pressure which causes her pain. Has anyone had success with finding something that works in a recliner chair that will help her be more upright so she isn't constantly uncomfortable? Any suggestions. I'm open to anything.