How can I remotely disable iMessage on ipad without having to remove from Apple ID

Question

When I moved to the USA I purchased an iPad for my parents who are very technologically challenged so I have them connected to my Apple ID.
Recently my husband and I have been getting a recurring notification that they have signed into iMessage using one of our phone numbers. I have called them and talked them through how to turn it off but somehow they keep turning it back on.
It is at the point I feel like I cant speak freely in text messages because at any point they could be watching.
I have looked under devices and their iPad is not showing up for some reason.
Basically I would like to permanently delete iMessage from their iPad but I do not have physical access to the iPad.
Please help!!!

Answer 1

IMAP is the mail protocol that allows you to delete a message one place and have it delete everywhere else. iCloud uses IMAP, so it should be working. If the messages never delete, then something may be incorrect in the settings. The easiest thing to do with iCloud is to logout of the account on every device, and then login again. (Another common problem with iCloud email is people often have two Apple IDs, and thus may have two iCloud email accounts. If you get confused about which one you're using, you may think you've deleted email when you actually haven't.)
If the iCloud messages do ultimately delete across all devices, then it could be that some devices aren't set to "Push" but are instead set to "Fetch" the newest info from the server. Fetch can be set to as long as an hour between check-ins.
The same holds true for Windstream if she's using an IMAP account there, too. If it's a POP account, then deleting a message one place will never delete it anywhere else—that's the way POP works.