I'm only familiar with the OWoD, but.... damn... Even with the broken ass power levels possible in that game that character is waaay off balance.
Advice: Fight fire with fire, build a badass NPC, kill the bastard, have him start a new character. Can't come up with a badass, borrow Kincaid from Dresden, Alucard or Paladin Anderson from Hellsing, or Dante from Devil May Cry, file off the serial numbers (or not, your choice) and pound him into the ground. Then set his ashes on fire, then put the fire out with holy water.
Good advice: Read the rulebooks, point out the rules that this guy is breaking to him, and ask him nicely to create a new character more in line with the rules. If that doesn't work, the good advice varient on the advice is, if this guy is so badass, he's GOT to have stepped on at least a few toes, even dead guys will have sires, childer, what have you, group a few of them together with the specific purpose of taking the guy out.
Best advice: Find a system all of you can learn together and start a new game from scratch, if its really about the role-playing you'll get a few converts.
My $.02... well, with the length of the post, more like a buck fifty...
dreadviking