As a former care giver I can say that this is a great idea. I think it would be a good idea to think about different interests to focus on for the quilt. With my dad, things needed to be mechanical to hold his attention. A zipper would work but buttons would never catch his eye. He also could not stand something that was not straight with the world so if I were to make something for him I would figure out a way to put something a little off kilter so he could try to straighten it.
Something else to keep in mind is that they also often see things that are very dark as holes. I would often need to be creative in ways to cover up holes. Like a rug in front of his chair to make a bridge for him to walk on or roll his wheelchair over. I did make him a place mat with the plate in the middle and could put finger food on the plate for his snacks.
I could keep him busy for hours with a butter tub with old nuts and bolts to sort or mixed beans to sort. He also loved keys so I gave him old keys to add to a key chain.
Other suggestions would be to add an adding machine shape with numbers, a clock face, perhaps some simple tool shapes, work gloves, puzzle shapes, a shoe with shoe strings to tie, snaps (big ones to snap together), pockets to stick things in (or find something) or a TV remote shape.
The thing to remember is that even if the loved one gets bored with this in a little while it will be all new to them again and again. I want to personally say THANK YOU to your group for thinking to do this and caring.