I think he is fairly young.
I haven't watched the whole video or read the comments.
I don't think he knows much about safety. At one point he says something like "I hold my breath while doing this.", something about removing zinc from some wires. Zinc vapors are dangerous to breath but holding your breath in a closed room wouldn't be good enough.
At another point he checks for a good seal by holding a HV wire in his hand near the part. He is trusting the wire insulation a lot.
I think what he is doing is more in line with scientific experiments before 1900 or Thomson type tubes.
http://www.crtsite.com/page3.html