How to update a field in one module when a field in another module is modified

How to update a field in one module when a field in another module is modified

I have two fields in two modules that are the same.  I would like to be able to automatically update the parent fields from the child fields but have not been able to create the correct workflow rule or deluge script to do this.
 
Parent form - INITIAL EVAL
      Fields - Plan (txt) and Restrictions (multiselect)
 
Child form - Events
     Fields - Plan (txt) and Restrictions (multiselect)
 
I want the fields in the parent form to automatically update when ever the child fields are updated. 
 
I have a daily report that goes out.  The accounts are chosen to be on the report by a check box on the Parent Form (INITIAL EVAL).  The body of the report I want to get from the Child form (Events) but I can't figure out how to select just the most current (Events) data for the report.  I can choose a specific day (Today) but if the account event was 2 days ago, It does not show up.  Likewise, if I include a date range...multiple events for the same account are listed.  I only want the most current (Created or modified).
 
Since I haven't figured out how to get this report to run, I have created fileds on the parent form identical to the child form and re-type the info, then run the report based on the active (check boxed) INITIAL EVAL. 
 
If someone knows how to generate a report with only the most currently modified event - that is really what I want.
 
Otherwise, if someone knows how to auto update fields form one module based on modifying fields in a different module, this would also accomplish my task.
 
Any help would be greatly appreciated.