Odds are they were fired
Technically, it is speculation as to why they are no longer employed. But unless the company is always cagey, odds are they were fired (or told to resign immediately). People don’t give evasive answers unless they have something to hide.
“x employee is no longer is employed by XYZ company” is an evasive answer.
EDIT: I think you are all missing that this is a question by a co-worker/work friend of the "no longer employed". Sure, you might get the form response if you just randomly sent the person an email. If the person were removed from the situation, then sure it could reasonably be open-ended. But this guy appears to have abruptly disappeared and even within the company, people are giving evasive answers.