Your wife has definitely attempted to murder your wife. But as she is your wife, try to talk to her. Convince her that your is not a danger. And you are willing to give him his share of the ancestral property. That property is his as much as yours. So, she shouldn’t try to kill him.
After that observe her whether she is trying to kill your brother or not.
If she still tries to do anything harmful to your brother then you can file a case against her under section 307 of IPC-Attempt to Murder.