I have to say this is my question as well. That's why the end of this show sucks. I don't think the brother did anything wrong. In the first place, the Mother killed the woman in order to keep her baby to be her successor in the name of protecting the island. I think that is evil.

I don't think the black smoke monster is Jacob's brother. Because in the last episode, Jacob threw his brother into the light cave and black smoke came out. Then he found his brother lay in the creek. He placed his brother next to his Mother in the cave they lived. Then there was a flash to the date Jack and Kate found the cave for fresh water. They found two bodies and said "one of them is female". To me this means Jacob's brother already dead. Just like Locke, the black smoke claimed Jacob's brother's body.

Another question for me is the brother can see their dead mother but Jacob can't. When the brother asked their dead mother why Jacob's can't see her. She replied "because I'm dead". What does that mean?

Ignorance is bliss.

MIB thought that people were naturally bad and Jacob thought people were good. They both brought people to the island to test them and see. In my mind.. that’s an evil thing to do

I’m confused, MiB (before he ever turned that way) didn’t seem the slightest evil? Seems to me that all he wanted to do, was get off the island however is ‘mother’ and Jacob forced him to stay, which I personally don’t think is right? Couldn’t this all have been prevented if they allowed him to leave? Or would he still be the same person even if he did? Confused...