How to deal with pushing

Hello I'm after some advice please. My 3 year old has taken to pushing, pinching, hitting and grabbing his 18 month old brother. I feel like I've tried everything...positive behaviour charts, stickers when he's being nice to him etc, the quite plain don't do hat because... and ignoring him too. I've spoken to his nursery who were shocked to hear of my son's behaviour as he he is very well behaved in nursery they tell me. I'm glad of that but just wish he'dbe kinder to his brother. Oh and the naughty step doesn't work either. He does love reading and i wondered if anyone knew of a good book about a similar situation aimed at toddlers or younger children. Any ideas would be greatfully received. Many thanks x