Most of the care facilities for seniors take on volunteers. As an adult I did this for 7 years in my spare time. It's very rewarding as a person gets to form a bond/friendship with the people they visit and help out. It can be one on one visitations or helping the recreation therapists with their programs for the residents. Just go to any facility and ask if your daughters could volunteer their time.
You could also contact Calgary Special Olympics as I know they are always looking for volunteers.
https://www.specialolympicscalgary.ca/
I did something similar with Foothills Special Olympics here in High River for 6 years and was a coach for various sports including softball and bowling. Working with kids and young adults with disabilities is very rewarding.