With brothers you become friends. Some you hang out with more than others. You talk to one about the other a little more. You get mad at them. Then, you love them. Then, you apologize. You have to apologize whether you want to or not. You have to. That's your brother.
I would fix other people's lines if they asked me on occasion. The hard part of writing is the architecture of it, getting the story and structuring it. Not the tweaking of lines.
A lot of people give in to those pressures and let others influence the process on their second albums because they want to achieve the success they had with their first again, but they don't know how to do it.

