Was I wrong?

[knittynoodle]

SIL has never disciplined her little boy. She has a lot of help from MIL (ie he lives there some of the time, MIL feeds him and looks after him) and whenever the boy is naughty, she passes him to someone else and says 'Go to nanny/aunty/uncle/anyone else nearby. Me and DP have discussed it as our little boy has taken a hit from this child many times. Hes 20mo.

Tonight, as I was sat on the floor feeding our 8mo, he came up behind me and pulled my hair. No one said a word. The second time he was literally hanging on my hair, I turned and said 'NO' but no one else said anything. DP rolled his eyes as if to say, its ok we'll talk about it later. Then nephew actually took a run up from behind me and punched me in the face from behind. My glasses are broken. I held him arm (because he was going to punch me again) and said 'NEPHEWS NAME, NO' in a firmer voice.

SIL began verbally attacking me and said I need to learn not to handle a child like that. I said if she had ever said No to him in anyway ever, he might not be hitting everyone at the moment. DP is fuming. Im fuming. We left at that point. I never hit the child or anything like that, I just held his arm from hitting me again.

Was I wrong to have told him off?

TBH until now, DP ahas been the only one who has ever said no to the boy.

He was hitting my son on the head and MIL took his hand and said Hit uncle instead!

Theres no hope, is there.

YANBU, make her pay for new glasses.

Yes, there is hope.
If the boy sees you and your DP as likeable, interesting and on his side, then it's perfectly possible for you communicate to him what is and isn't acceptable behaviour.
I don't expect you SIL will make this easy for you (and FWIW, I think parents who refuse to set boundaries in this way are burying their heads in the sand about other problems which have nothing to do with DCs).
But there is hope.

YANBU, make her pay for new glasses.

Absolutely.

And next time he punches you in the face, punch his mother in the face. Might make her think a bit more about her own inaction.

that boy should be on the naughty step or having time out in a bedroom! I'm so shocked that they think its ok for him to hit everyone - infact they seem to encourage him. we don't tolerate any violence at all here and it's straight to the bedroom for a long think if anything at all happens - which is very very rare. some people think that boys will be physical but really boys are only as physical as you let them be and he sounds like he is out of control. you were right to protect yourself. why should you let him hurt you? i'm glad FIL said something. do you think your DH could talk to parents about whats going on. maybe they need the super nanny book?

My DS1 is 21 months old. He is a hitter. He is consistently told "NO. You DO NOT HIT. IT HURTS. If you do it again you will sit on the step for 1 minute" if he does it again off he goes whilst I cuddle the hitee.

He is still hitting. Normally children, usually over toys and 'sharing' I have to watch him like a hawk. I live in constant fear of social exclusion (for both of us).

Maybe SIL is humiliated by child's behaviour and feels if she tells him off it draws attention to it.

If I discipline DS1 for hitting I am usually told by hitee's parent "Oh don't shout at him, he is only little, he doesn't mean it" AAAAGGGGGGGRRRAAH Yes he does mena it, the only way he can express his emotions is through violence.

Anyway I digress, YANBU, if you pipe up maybe she will follow the lead?

A stern NO was exactly the right thing to do, at 20 mo I'm guessing he's not brilliant at talking yet but perfectly able to understand when they are doing something that they shouldn't.
Good luck with your SIL.

you always see the same pattern: the children with ridiculously lax parents who allow them to hit without being told off end up by Year 3 or Year 4 as the kids with who never get invited on play dates and get excluded from class parties because the other kids are wary of them and the other parents refuse to deal with their bad behaviour.

Very true-happens every time -it is such a pity that the parent gives them such a handicap for life.

I think your DH should have stood up the first time the little boy hit you and said to his sister, "Are you waiting for one of us to deal with this?"

He should have been the one to take the boy to one side and explain why you don't hit.

You were on the floor with another child. Your SIL obviously wasn't going to shift herself. He should have dealt with it in the absence of the boy's mum doing anything.

And then he should have come in with the boy ready to apologise, then said to his sister, "Why don't you ever try to discipline him? Can't you see that he'll have no friends when he grows up if he carries on like this?"

The difference is though stranded you tell your Dd no and that's the only way she will learn, that's what missing in the instance of the op.

Ds is 20 months and he does know when he has been pushing his luck mostly and if he does something wrong I tell him as that's the only way he will develop that awareness

Of course YANBU. Make her pay for your glasses repairs. And you weren't wrong to tell him no and hold his arm. I feel sorry for him; he will suffer for his lack of boundaries and bad behaviour later on but it isn't his fault.