Part of what happens when I try to explain this to others is that I talk about individual issues, but it requires self-examination to get to the root of what's happening, because it's not happening in a vacuum. What's happening here is the definition of enabling.
You don't notice it's happening at first, especially when it's a person who lives far away whom you don't interact with every day. It's not the same intense emotional drain as it is when it's someone in your household, but same thing.