I took care of my Mom and Dad for many years. It's an incredibley difficult venture, but one if approached with love can be bittersweet and humbling in many ways.
The gradual loss of independence and in some cases dignity is MUCH harder for them it is for any of us.
Cleaning up my Mom after she would have bathroom accidents was a very humbling experience for both of us. As she lay there in a total mess, I was trying hard as I could to not let tears stream down my face, because I understood how humiliated she felt. She had Alzheimers as well as Breast Cancer and the combo of both took her life. She struggled for many years.
While she was struggling my Dad had many health/mental struggles of his own. Too numerous to count and oft times he was incapable of taking care of her. When she passed away he lost the will to carry on and passed on a year after she did.
It's hard stuff.