First off, I work in a bureaucratic limited funding environment. I'm not able to get whatever add-on that might make this simpler (which seems to be the simple answer everyone seems to come up with). I have scriptrunner for Jira, and I have Power Custom Fields Premium, and it's a 6 month process to get addons approved here.
I need to be able to copy comments from sub-tasks to the parent task. It doesn't have to be pretty, but only my techs touch the sub-tasks while my managers are monitoring the parents and can't seem to keep track of the dozen sub-tasks they are tracking amongst hundreds of requirements.