We have three adult children. We help them financially when needed.

Thankfully that's not often.

Re health problems, we expect to spend an average amount beyond what's covered by Medicare (recently that was estimated at around $315k - https://www.usatoday.com/money/blueprint/retirement/healthcare-costs-in-retirement/).

Is it possible things won't work out?

Sure. But we're doing what we can to minimize that likelihood and to minimize its impact if it comes about.