Initially makes me wonder how the employer could be so dumb as to give one employee so much access. But then I remember a former employer of mine did the same and worse.
Colleague was known for writing his comments in such a way that only he could read them, including mixing in German (US based company doing all business in English). He was also the admin of our CAD system and would use it as leverage to get his way on things, including not giving even default user access to engineers he didn't like. We migrated systems and everyone was thinking, "this is it, the chance to root this guy out of the admin position" and... they gave him admin access again. Not even our IT department had the access he had. I left before the guy retired / was fired, this post is making me wonder if he left peacefully or left bricking the CAD system out.