Update a parent record upon child form completion

I want a parent field to be updated one a complete a form, but for som reason, I won’t work.
I’m creating a rental app with four main entities (tables) :

  1. Customers (my list of customers)
  2. Rentals (all the rentals I created)
  3. Departures (infos added to a rental when the customer take the item with him)
  4. Returns (infos added to a rental when the customer return the item)

Each rental goes through CRM-like status (field in the #2 Rentals table) :

  1. Prospect, 2. Confirmed, 3. Rented, 4. Returned, 5. Cancelled

My problem is when my employees create a form in #3 Departure and #4 Returns, I want this status field in the parent table to be updated be on a record rule : from 2. Confirmed to 3. Rented and from 3. Rented to 4. Returned respectively.

I’ve setup the record rule the correct way (maybe not?), but this connected field isn’t update neither in the parent table or in the Departures/Returns tables as well.

What I’m I missing here?