My wife passed away in June, 18 months after being diagnosed with cancer. The cancer was incurable from the beginning and when the chemo stopped working, she was told she had 6 weeks - 6 months to live. 2 weeks later she went into hospital with a temperature and after being examined we were told she now only had days. Her condition deteriorated very quickly and she died 5 days later.
Even with all the time we had knowing she was dying, we still weren't prepared.
We didn't manage everything she wanted to do, but I imagine her only regret will be not seeing our daughter grow up.
I agree with others, power of attorney and having a will in place is essential.