Any tips for helping elderly bed-ridden mother with curved spine sit straight while eating and taking pills?

My mother's back curvature, which causes her to lean dramatically to the right, is making it more and more difficult for her to sit up straight enough and long enough to eat her meals and take her meds. This is while she is in bed, but it's also getting to be a problem when she is in her wheelchair in the mornings. Can't seem to hit on a configuration of pillows that really helps enough. She never complains that anything (her neck, back, etc) hurts, but dementia keeps her from reporting very accurately about anything these days. I thought someone might have hit on a technique or product that works especially well. Thanks.