Once someone is a merit source, he is not a source for lifetime. Merit source list is updated every month. If a merit source is inactive in the forum for a long time or does not distribute the Smerit given to him, then he is removed from the list of merit sources.
Oh boy...
For example, this
user is on the 109 Merit Sources list since 2019 and is still there. And there are others like him. So we can conclude that it's better not to write something when you don't know much about it.