Disable/Stop existing threads that recipient is involved in when recipient permission/role is removed.

Problem/Motivation

I created PM role to allow users to use the private message system.
Members who do not have this role cannot create or receive new messages. Everything works fine up to this point.
But when I remove this role from a user, if they have previously been included in a thread, the messaging continues. And the person who wrote the message continues to send messages because they do not know whether the recipient has this permission or because there is no warning. And they may think that their messages are not being replied.
If the recipient's permission is removed, the person who will create the message should either be shown a warning or, as in the ban system, message sending form must be disabled.

This isn't just about permissions being removed by the admin. Users should have the freedom to turn off the private messaging system for their account or leave a thread, rather than individually blocking other members or deleting PM threads.

Any idea, Please ?
Thanks