I'm in compete shock.....

Dont leave them alone next time. My son is three months old and i will never leave him unattended with another child . Since there childs they dont know from right to wrong . So maybe next time keep an eye on them or just completely stop your 4yr old from playing with him. Till your 3month old is capable from defending himself or have the ability to scream for help .

I was sitting right next them. I took my eyes off of them for a second. I already mentioned that in the OP. I never leave my son unattended with his brother. I just don't understand why he'd even do that.

That doesn't sound like normal 4 year old behavior to me. Have you talked to him and asked him why he would do that to his little brother? And ask him if he knows that could hurt him really badly? I think you and him need to sit down and have a talk about it and let him know it's not okay to do things like that to anyone! He could have honestly just been trying to play with him, but I think after a talk, tell him he's not allowed to play with him unless there is adult supervision. Just lay out the rules now. So he knows them, and if anything like that ever happens again, then you know he meant to do it, and you could go from there. Because I don't think that's just sibling stuff. Not trying to be mean at all! That's just what I would do in your situation!

He seems jealous. When so was three he put a pillow over his newborn sister when they brought her home from the hospital. He was jealous of her. Maybe just mAke sure to give him attention and not leave him out?

Unfortunately kids that age act out in rather unexpected ways and they don't have to be learned behaviors. In his defense, they have no idea the nature of the damage they can cause. Doesn't mean it shouldn't be sternly corrected and watched for, but try not to be too alarmed or think he's gone off the deep end.

It's jealousy. My older son once smashed a metal toy car into the back of his brother's head. It's terrifying.

It's a very scary situation. I did have a talk with him and he said that he didn't know why he did it. ? I told him that he could've really hurt him or even possibly killed him. I'm at loss for words and I just know how what else I could say or do.

This happened yesterday afternoon and today he's still been rough with him. They are both in my sight 24/7. I really hope and pray he doesn't do it again. My SO doesn't even know what to say or do. ?

@ocean no. He was playing peekaboo before he did it. I don't think this is jealously. This has to be something else but I pray it's not. Like I said today he has still been very rough with him. I redirect him every time he does but it seems to not work because he goes right back and does it again.

To your son it could have been a simple game of peek a boo. You just have to watch him around baby.

My 4 yr old was throwing the blanket over his head saying peekaboo and then he put it on his brothers face and was holding it down with excessive force. So I don't believe that it was just peekaboo this time around.

Thank you ladies for all the advice! I really appreciate it.

I think it was him playing not knowing what he was doing and when you saw him he got hit for playing with his brother, so now why would he be nice to his brother? That's probably why he doesn't like him now.

I think in this instance, gentle parenting could've been better than hurting him for hurting someone, when he didn't know he was hurting the baby.

I feel awful for spanking him and I apologized for doing so. I didn't even think before I did so. ?

He's been rough with him for awhile. I always redirect him. He knows gentle playing vs rough playing. I don't know much more what I can do if I been redirecting him and he just won't listen.

This is so scary to even grasp rn. My son is 4 almost 5 and I've never ever seen behavior like this. I do have a 6 year old so idk if having an older brother has taught him more how to be a brother and learn boundaries rather then just being an only child like your son was before. Keep redirecting him. I think removing the baby will only cause more resentment if there is any. He just needs to learn to adjust to a new baby like everyone else hes learning how to be a big brother who needs to be taught boundaries.

Instead of redirecting him when he is rough, try explaining to him he needs to be gentle. If he continues to be rough, put him in time out. I have an almost 2 year old and an almost 3 month old. Ds1 didn't stop being rough until I explained how he could hurt ds2 anout 50 times. The time out chair was the perfect tool. Now, even if he bumps into the baby he immediately says sorry to his brother and then runs to me and says sorry. If you consistently redirect, he will never know he is being too rough.