Maybe plaace some pockets on it with small stuffed animals or a ball or something like that. these could be attached with cord and they could be washable also.
I grew up with a blind cousin, and he had a bag of things that he felt , when he was little , dried fruit, toys. Also terri cloth has a great feel. You could tie it instead of quilting it, and he could feel the knots. You can get cotton with raised polka dots.
Or you could quilt different shapes in it and use a deep pile batting , so the different shapes would stand up!
Just a few, hope this helps some.