Why do I hate my job, you ask? Because I spend my days negotiating wills--contracts that bind the living to the dead. I stand on the threshold between Here and There.

The story is already all enshrined here. We are immersed in the intimacy of a first-person narration, with the character talking about her life. An amazing hook that engages the reader from the opening line.
This is how stories should be written.

After that, my attention started to decline slightly due to the explanation (show don't tell rule) yet it's been sustained by the pleasant structure of the sentences. And then...

My job? See that the daughter became beneficiary, keep the revised will secret.

What a twist! The protagonist shows her evil side. Who would have ever told?

Overall I see your ending as a well-crafted preface to a promising series of episodes. Credit goes to your research of fine concepts about the thin line between living and dead and their interaction, very clever musings that adorn the whole story.