Accept your limitations. No one person can do it all. Ask for help from other family members if available. Don't force your own expectations on your loved one. Accept their refusal of the plans you have made.
Many older adults fear loss of independence far more than illness or dying.
Spend some time documenting the details. Maintain a file with all the financial and legal information you will need later on. Don't blame yourself if a crisis happens, they are often inevitable despite your best efforts. The crisis may validate your care plans, but this is not the time to say I told you so. Don't be afraid to cry, you need an outlet for your for your feelings.