The request here is prevent a parent work Item for being closed while there are still child work items not in a conclusion state.

It could work like Workflow in Jira where you can determine conditions for that work item to be closed as in the KB link below.

https://support.atlassian.com/jira/kb/how-to-prevent-issues-from-being-closed-while-the-sub-tasks-are-still-open-in-jira/

In this case we are talking specifically about Epics.
This is true in all levels.