Yes it would, that's what happens to poor metabolizers. His body couldn't break down the drug (or it's metabolite DXO) like most people can, so he got significant effects from a small amount, that lasted much longer than they normally would.
As for the thread topic, no it's not an ideal beginner's entheogen/hallucinogen, it's just too variable, and is only enjoyed by a minority of persons. Still, a lot of folks start with it because they have nothing else available (at least they're trying out one of the less abusable dissociatives, I say). Also, there are a number of significant contraindications with this one. Any of the classic psychedelics would make a superior starting point, or your average 4-sub-tryptamine, or 2c-x (besides 2c-p/g/the long ones), et al.