Zane wasn't dead. They opened with the shootout at Nick Ford's place but Zane wasn't among the bodies. Remember that Sheriff Romero is looking for him and assaults/harasses Dylan in order to send a message.

Zane later shows up at Jodie's house where he and Jodie and Dylan have a meeting. Zane doesn't trust his sister and obliquely warns Dylan before leaving.

Nick Ford and Dylan have the meet at the diner where Nick orders Dylan to kill Zane and threatens all out war and Dylan's family.

Dylan threatens Ford in turn but later goes back to Jodie's house where he tells her that she has to stop Zane. She orders him out but then embraces him and whispers that if he has to (ahem) "stop" Zane, then she's ok with it.

"When the snows fall and the white winds blow, the lone wolf dies but the pack survives."
Winter is Coming

Now this is the Law of the Jungle—as old and as true as the sky; And the wolf that shall keep it may prosper, but the wolf that shall break it must die.
As the creeper that girdles the tree-trunk, the Law runneth forward and back; For the strength of the Pack is the Wolf, and the strength of the Wolf is the Pack.