Prepare, prepare, prepare...
If you are pretty sure you'll play a role in caring for a parent, it's never too soon to start preparing! Even if just mentally thinking through what you would and wouldn't be ok doing. Would you move cross country to care for them? Take them into your home? Do you know their financial and medical connections? Do they have assets for themselves, and/or would they qualify for Medicaid? These are just a few things to start researching now. Don't wait for the crisis to hit...