No way would Christopher have been anything if it wasn't for Tony. He was too reckless in the early seasons, and too much of a junkie in the later ones. I don't know if he would have been clipped along with Brendan (although it would be likely given that Tony basically saved his bacon from that situation; if he wasn't related would Tony have done that?), but he probably wouldn't have been given as many opportunities to get ahead.
There's a chance he might have become a made guy, but even if he did he would have never amounted to more than that.
Had he not put those storm windows in for Livia when he was younger, he would have been a goner.
