Hitting

So my nearly 2 year old has autism. We are in the process of having it diagnosed but from working with it its something I know he has. He's very simulated by hitting and slapping on legs and objects and really hurts. Recently he has become a nightmare. When told off or asked to stop he will go out of his way to hit and kick and it's not always directed at the person who's upset him. He will throw himself on you and repeatedly slap and has started to kick and will target his 1 year old brother who just loves hum and wants to snuggle him. It's the slapping that hurts as he's a not so little child. It's becoming very overwhelming for me and if I'm being honest this past week has just been met with my anger. Can anyone please give me some advice on how they have handled these types of behaviours and what's worked for them as I don't want to feel angry at him all the time for him trying to express himself but it's so hard not to meet his anger with anger if that makes sense. He's also none verbal which doesn't help. He understands but like any child doesn't like to be told no or to stop