How to auto Fetch From field, when the origin document change its value?

In ERPNext, there is a useful “Fetch From” field.

For example, In a new document with Employee field, we can add field “Employee Status”, which can fetch from employee.status during its creation.

But when the Employee Status is changed, i.e., from Active to Inactive. I want the Employee Status to change accordingly.

From what I understand, it is not possible to do it at the new doctype itself., but rather have to code in the Employee’s on_update event.

Are there better way to do this?