the leg line art look rather crooked along with blue's arms

I quite like this! The blue and red brush strokes look like wet brush strokes, and the guys look like pen, so I quite like that. However you could emphasise on these stroke to give a hint on what the characters are like, and maybe try and finding a way to connect both characters, because yin+yang=harmony: I would add a third colour.

I think this could use a lot more cleaning up.
Your brother's head doesn't seem to be attached to a neck, You also got to try and let yourself draw hands, don't try and hide them.

Your brothers close arm is too thin.
And I'm not too big on their legs.
Yours is okay but his is missing a chunk.