DS is nearly 4, DD nearly 2. He never really took to her (well, it's understandable - he was the centre of his little universe until she turned up). I've read Sibling Rivalry and found it had lots of good advice which I have been following, hoping it will pay off eventually.
But it doesn't say what to do about the hitting, pushing over, sitting on and biting that is now part of DD and DS's daily lives. At present it's one-way, but I can see the time coming when she's as inclined to lash out as he is - she's already started to say 'DS, I will throw you away' and 'horrid mummy' - just repeating what she hears at least 3 times a day. Poor DS is in a constant state of simmering resentment, which flares up at least once an hour. it's exhausting and makes me snappier and snappier with him, which DD picks up on and provokes him to greater outrages so I sometimes feel (like today) that i've spent the entire day separating them, putting DS in time-out, letting DD choose the telly program to watch as a punishment, etc, all of which just makes DS behave even more violently towards DD and we're in this crappy cycle that I can't seem to break.
Believe me, I have huge sympathy for DS. He's only a baby himself and I know he's hurting, but we can't get rid of DD now, even if we wanted to, and I really think that this is the only thing that would make him happy again! What on earth can I do???? I don't expect him to like her or love her, I just want him to stop trying to hurt her. All advice most gratefully received!