Who is asking

In 2022, [what the donation site at the Robert Schuman Hospital was, in a sentence: who it was for and what people brought].

That is where Leonard and Alex met. [How: what each of them was doing there, and what they noticed about the people who came].

[What stayed with them afterwards. The question that neither of them could answer to their own satisfaction].

So they decided to ask other people, one at a time, and record what they said. That became The Cost.