It's a pretty perfect situation. Lily loves to entertain Finn and he loves to be entertained by her. She cracks him up like none of the rest of us can. He perks up when he hears her shrill little voice, as I call it. He loves her repetitiveness. "Who's a cute baby? Who's a cute baby? Who's a cute baby? Who's a cute baby? Who's a cute baby?" If he hears her talking at 6 a.m., he will wake up. (But we try to usher her out of the room as quickly as possible so he sleeps until 7 or 7:30.)
She likes to dress him up or "decorate" him. She sings, she dances, she plays peek-a-boo. He's perfectly fine with all of it, even preferring her play to ours at times. His patience is enviable.
We're very happy they get along because she could easily ignore him or be mean to him or make him cry on purpose. And he could scream, ignore her or not laugh at how truly funny she is. It's nice to have two.