Marie, I would say that certainly made a big difference for your Mom. I don't think making a difference has to be a huge thing. It can be constant little things which end up being very huge in the end.
I helped take care of both of my Grandmothers before they died. I used to do quite a lot of housework for them and help them with things from hygiene to going to the grocery store or planting some flowers for them. I am very happy I was able to do what I did to help out. Some things I cannot do myself...but I could do a lot to help them in small ways.
I would hope that I helped my patients when I worked in the medical field by caring for them each day in my job duties and some extras along the way. I also use to volunteer at an alzheimers home and an adult foster care home. I think though in the end I got a lot of satisfaction from the work and the patients. A lot of laughs too. The difference in people's personalities can be uplifting.
I helped my aunt when she had some some life changing serious surgery and cancer as well and was in a nursing home on a respirator for over 6 months. I knew some things directly about what she was going through partially and talked to her and visited with her often. Right before her passing she called me on the phone and she asked me how I had lived with what I had for years, and how I had peace and I shared my faith with her and that conversation is a treasured one to me. It was very loving.