Based off the first and only screenshot I can see it looks like you are trying to do replication through a lookup. This is typically done using SOQL.
You'll want to confirm the API Names but the query would look something like...
SELECT Id, Name, Medical_Record__r.Name, FROM Application__c WHERE Course.Id = '<<Course_Id>>'
If this answer is correct please mark this as correct.
Thanks, @ryan_oleary I am not trying to do a lookup relationship. I was just trying everything I could to see if I could get the system to stop deleting the child object as an option to create other relationships.