Thread:Brandon Rhea/@comment-47034773-20201001182655/@comment-1038387-20201001184213

"Necroposting" refers to someone adding a reply to a long dead discussion. It gives people useless notifications and adds nothing to the discussion. That can create frustration.

A general rule of thumb in terms of net etiquette is, don't reply to a thread if the last reply was 3-4 days ago. Though your brother might want to check local guidelines to see if there is a different policy.