How do you define a seniority in a corporate is beyond me.
This guy is supposed to be Tier3, literally "advanced technical support". Taking care of network boxes, which are more or less linux servers. The most knowledgable person on the topic, when Tier1 screws something and it's not BAU/Tier2 can't fix it.
In the past hour he:
- attempted to 'cd' to a file and wondered why he got an error
- has no idea how to spell 'md5sum'
- syntax for 'cp' command had to be spelled out to him letter by letter
- has only vague idea how SSH key setup works (can do it only if sombody prepares him the commands)
- was confused how to 'grep' a string from a logfile

This is not something new and fancy he had no time to learn yet. These things are the same past 20-30 years. I used to feel sorry for US guys getting fired due to their work being outsourced to us but that is no longer the case. Our average IT college drop-out could handle maintenance better than some of these people.