There is no "answer' when caring for an elderly, disabled parent.
Except to turn the caring over to someone else. Check your particular state for any and all resources. Caregiver Burnout is becoming more recognized, and private non-profit as well as municipal entities are starting to address this to help us cope.
A parent's trajectory is not going to change. The dye has been cast, so to speak. But we as caregivers do have choices whether to continue in our own downward spiral or change the situation. The biggest hurdle to get over is the emotional element that often keeps us locked into a desperate situation.