This is not possible unfortunately.
I have achieve something like this in the past, but it took a fair bit of work, and it relied on having the same set of fields in all three records (grandparent, parent, child) and a mechanism to update the fields when a change is made
Option 1 - Field Mapping - this option only works if you are creating parent/child from a subgrid
- Set up field mapping to pass the fields from the grandparent to the parent (assuming this is created from a subgrid within grandparent, and repeat the same for passing from parent to child)
- Limitations - if the field values update in a higher record, they are not updated in the lower one automatically
Option 2: Javascript - only works if records are created only from the UI (i.e. not by some other means, like a Flow)
- Write a script to run on save of a child record to get the grandparent record (via the parent record), and write the fields to fields with the same name in the child record.
- Limitations: field values in the child record will only update when the record is saved. If the app is heavily used, with lots of saving of child records, this could consume a lot of API calls.
Option 3 - Flow
- Write a flow that runs on create on a child, finding the parent, then the grandparent, and write to a set of fields on the childs record
- Write a second flow that when a grandparent record is updated, list parents related to the grandparent, and write data to the relevent fields on parent, then list children of the parent, and write to those fields (you could skip writing to the parent, and just write to the children if you prefer)
- limitations - again, could use a lot of API calls in an app that is heavily used
Happy to discuss either of the above options in more detail if these seem suitable
