First of all, sorry for your current family situation. I've been there with my parents, and it is tough.
Regarding fares, as others have said, basically it's gotten more difficult (restrictive) in the past 10-15 years (or more) as flexible fares, discount fares, etc. are available. For example, I can get to NYC for $318 next week. A bereavement fare is like $950+. So why bother.

In your case, I would call Delta and plead your case... or just see if you can cancel out a return leg and book a new R/T to wherever you're coming from (or a 3-way if that is required).

Or... use miles.