These look like the old Scimitar Bronze series that Zildjian put out in the 80's or 90's. These are student level cymbals and are not great quality to begin with. The level of discoloring on them is quite severe, but I don't think your buddy is 100% at fault for this. Maybe they were kept in a damp environment for some time.
I would have instantly fired that "friend". I use barkeeper's friend on all of my traditional finish cymbals, too. It will remove the logos, but I don't give a shit about them. I'm not out to advertise for Zildjian, lol. For my brilliant finish cymbals, I use regular old turtle wax car finish polishing compound. Works great, but also eventually scrubs off the logos, for anyone who cares about that.
Just skimmed through the video didn’t really pay attention to how long you said you left the BKF on there for. But I’m sure if you left it on for longer that would look good as new. P.s. buddy owes you some new cymbals lol
