May I ask why your mother never joined in? Was there activity co-ordinators there trying to encourage her? If your mother was in the new care home I shall be working in (very excited) - any tips how I can reach out to her so she gets fulfillment and joins in? or would she tell me and I would obviously respect her decision.
My mum loved joining in the activities when she was first in her care home, but as she progressed the activities became harder for her to do - even the simple ones. Eventually she was unable to do activities, but used to sit in the lounge and watch the group activities, which she seemed to enjoy and was enough stimulation for her.
One of the activities (not a group one) that the co-ordinator did was to put together Reminiscence Boxes - boxes containing items, pictures, models, etc that are designed to stimulate memories - which were given to a resident for them to rummage through, take things out and look at them. They could be general, designed around a particular theme (sewing, cooking DIY, etc) or designed for the individual with photos (use copies) and items relating to their history, hobbies etc.
I did two boxes for mums care home - one on a sewing theme: a sewing box containing thimble, tape measure, buttons of varying colours and shapes, length of elastic, bits of lace, squares of different fabrics, plastic needles (designed for children), pin cushion (no pins), darning mushroom, etc.
The other was on a DIY theme: a plastic box with a handle and removable tray containing penny washers, springy door stop, wooden rule, hinges, door bolt, realistic looking plastic models of tools (designed for children, but very realistic), plug, etc.
In other words, all sorts of pieces that would be used for that activity, but nothing sharp, dangerous, or that could be used as a weapon!!