Lets look at the development of a 2 and half year old.
He or she is growing rapidly, and the level of frustration he experiences on a daily basis is intense. He has strong legs and an active body, but no maturity to use them well.
His mind and body are full of big impulses, and these impulses are serving his development, but not always in ways that make sense to you. As inconvenient as he can be to your plans, his mind and body must begin to individuate. He could not grow into himself if he always did what he was told when he was told to do it. That is simply not the path of a human.
So there is naturally frustration built into the maturation system. His mind and body are seeking ways to satisfy his impulses, and your job is to keep him safe.
Whether you're stopping him from climbing on dangerous things or restraining him in a busy parking lot, you are almost constantly protecting him from himself.
The more the frustration in his young system builds, the more it spills into aggression against you and other family members.
Your child's world is not only full of no's, but he also has a big sister who can do everything faster and better. Furthermore, he doesn't have the language to express all of his big feelings.
This is all very, very frustrating. And the way frustration moves in all humans is that if you can't change it and you can't have your tears about it, it will come out as aggression.
And humans are never as aggressive or violent as when they are 2 years old. That may sound laughable, but think about it: Adults who hit and kicked and spat and bit and screamed and raged the way 2-year-olds do would be considered sociopaths.
I say this to normalise, normalise and normalise your child's behaviour. I am not saying it is good or convenient or fun. It is simply part of the maturation process, and if you don't punish him, give in to him or fear him, it will pass.
But how do we keep his sibling safe until his brain matures a little more?
1. Stop expecting him to change. Seriously, stop being shocked that he hits his sister. Simply expect that he will try to hit every day, maybe every hour. By dropping your behavioural expectations of your son, you can turn your attention to the behaviour you need to change: yours. I know this goes against the positive mantras that are given these days, but I have found that constantly expecting your child to change (without anything else changing in the environment) is a recipe for disappointment and more of the same. And remember: This is the most violent time in a human's life.
2. Make sure his routines (food, sleep and play) are on track and working for him. Each child is different, and each child changes with growth spurts. He can't tell you everything he needs; his brain is not working on that level yet. You must be able to investigate and think for him.
3. If he is chronically hitting his sister, you need to assume that he cannot be left alone with her. You are going to need to monitor him more. If this is exhausting or too time-consuming, you can create new ways for the children to play while you are doing other things. For instance, maybe they are peaceful when they watch a show, but any other time they are playing, a fight breaks out. This means that you do not leave their play up to them. I know this is inconvenient, but it is better than listening to your 5-year-old scream while you are losing your cool trying to figure out what to do with the 2 1/2-year-old.
4. Help the 5-year-old learn how to get away from her little brother. Have some quiet discussions with her about him. Tell her that he is doing his best, but when he gets angry, his cup tips over into hitting. Be sure to let her know that you and your husband are not okay with the hitting and that when her brother becomes angry, she needs to come to you right away. This strategy will require a lot of practice, and you must not get annoyed when your 5-year-old calls for you.
5. Do everything in your power to stop the first hit. Write down everything you think may be triggering him, even if it doesn't seem to make sense. Is there anything you can avoid? Anything that could be improved by getting down to his level and making eye contact? Is it hunger? Is it when he is tired? How can some of the tantrums be sidestepped? You would be surprised how often you can avoid tantrums when you take the time to unpack what is happening on a regular basis.
6. While you are stopping the aggression, it is best to stay as quiet as you can. Kneeling down, looking him in the eyes and saying, "Let's go get that hitting out somewhere else," may be enough to stop him from dissolving into a full-blown hitting episode. If your son appears out of control, talking, giving direction, pleading and making threats will only build more frustration. When the brain is hijacked with frustration (especially in a young child), it cannot register language (especially corrective language) well. There are emotions spilling everywhere, and the best you can do is to de-escalate the situation.
7. As gently and strongly as you can, help your son calm down. How this looks is different for each child. Some children like to be held. Others want you to stay nearby. Some like to hit other objects. Some just need you to listen while they rail against life's injustices. See what works for your child.
8. Keep your sense of humour and surround yourself with people who have one, too. I know that the hitting is distressing, but it is not Defcon 1 either.
9. Be unabashed with your love and affection, especially after your son has had a hitting episode. Contrary to what many people think, showing your son affection will not add to the hitting. Instead, if you separate the behaviour from the child, you will move through this stage more quickly.
10. Keep an eye on him as the years progress to make sure that there is nothing sensory going on. I don't know many paediatricians who would be shocked at a 2-year-old who hits, but you should still keep your doctor abreast of what is happening with your child. Be able to list how you have reacted and what you have done to prevent the hitting.
11. Begin a small library of child-development books. One of my favourite series for parents is by Louise Bates Ames, and the name of her book about 2-year-olds is Terrible or Tender. Deborah MacNamara's Rest, Play, Grow would also help you understand how young children mature and how parents can help facilitate their growth in simple ways.