A mast type panel holder on a tripod is a very versatile "easel" that can be used sitting in a chair or wheel chair, standing, sitting on the floor, laying / sitting on the edge of a bed, etc. A small shelf that attaches to the two front legs can hold the mixing palette, solvent / medium cups and brushes. Add a taboret on wheels to hold all the materials and you would have a compact and portable studio setup that could remain in place if desired but without losing the ability to adapt to different positions as needed.
This is one fairly nice version of many pre-made or do it yourself solutions out there ranging from very inexpensive to VERY expensive. I built mine from scratch for under $60 including the tripod.