How to query Related fields created in Query Issues Custom Fields

[QueryIssueUser]

I'm currently using Query Issues Custom field in my project. I have configured it as below.

Query issue linker custom field - CF1- JQL Clause - project ='XYZ' and issuetype='abc'

Query issue related custom field - CF2 -JQL Clause - CF1=RLINK 

It works as expected creating Parent and Child links.

I'm unable to use CustomField2 (RelatedFields) in JQL. The documentation says it's a read only field and Search Template for this custom field is also disabled.

How to get the list of all child tickets. Also, I would want to auto close the Parent ticket on closure of all of the child tickets.

Please advise.

[QueryIssueUser]

Could someone please advise