Sibling Love

Maxwell is starting to become friends with Frances. He'll play with her, as long as he gets to decide what he plays with and what she plays with.

He'll even let me sit them together on the couch.

He'll sit on her lap, and she'll tolerate the abuse, but Frances is not allowed to sit on his lap.

He enjoys it all, if Frances isn't trying to "bite" him or touch him. 

Clearly though, he is starting to love her a bit.