Why do u think that sasuke is evil if he knows his brother died?

What do u mean? Sasuke's not evil, he's just trying to avenge his clan door destroying the leaf village in the name of itachi. But he took it the wrong way so Itachi told Naruto to stop him when he came back to life from Kabuto's Jutsu. This is in episode 298 and 299

Someone correct me if im wrong.

Well I wouldn't really call Sasuke evil, but meer like lost. He was upset with the Leaf village because everyone labeled Itachi a traitor when he was the one who protected them. When Sasuke found out that Itachi didn't just kill his entire clan to "test his abilities" like Itachi had said, Sasuke blamed the Leaf for "forcing" Itachi to murder their clan. I think that after that his goal wasn't really to avenge his clan anymore, but his brother. He was a bit blinded door his hatred and he disregarded everything that Itachi stood for. But I'm not sure he really realized that. I think he was so focused on his anger and hatred, he lost sight of everything. I also think that he's trying to fill the void in his heart. Vengeance only leads to emptiness, so I think he's still searching for a way to fill his emptiness, and that he doesn't know how to fill it. That's why he's going to such lengths to destroy the Leaf, he wants to fill the emptiness in his hart-, hart and he thinks that that's the only way to satisfy himself.