Do you mean you want to show that right in the form? That’s not possible, because you don’t have access to that unit number value to create a relation.
I would suggest creating a custom form that:
Writes the unit number to a user-specific column.
Use relations & lookups to retrieve the tenant name and amount values.
If you want users to edit the name & amount, create a button that write the lookup values to 2 user-specific columns, and add entry components for them on the screen.