C likes to belly flop or just plain push E onto to the floor when she's walking. Bear in mind that she's only newly walking so she's a bit unsteady on her feet. He'll also hit her over the head with his toy sword which can actually be quite sore - he's done it to me before! If I tell him off he laughs and either later that day or the following day, he'll be back to doing it.
E isn't all innocent. She can hold her own and can retaliate. My dad has caught her hitting C (obviously she's picked that up from him) and she is beginning to snatch toys too. I do explain that she has to share but at 17 months, I'm not sure how much is going in. I have spoken to Chris about it and he thinks it's something that we just have to live with. Brothers and sister fight all the time. There is a ten year age gap between myself and my sister and I don't remember anything like this. Maybe it just happens with smaller age gaps?
I don't want to be a complete Debbie Downer. When they're good, they're really good. If C cries, E comforts her. If C hurts E and she cries, he'll immediately say sorry. They enjoy a cuddle together and C has recently started trying to lift E. It's really cute and he is strong enough to actually get her off the ground! E thinks it's great and laughs so much. When E wakes from her nap now, C will excitedly say, "Yay! The baby's awake! Wakey wakey!" He just loves having her around. We've had a few moments where they'll play nicely together but when they're quiet, they're usually up to mischief like drawing on the living room floor! They have both recently become massive fans of Frozen. C likes to sing Let It Go or Do You Wanna Build a Snowman? and E has started trying to join in. It's super cute hearing them sing their little duet together.