Harley is a ticking time bomb, which can go off when anyone least expects it. If OP'S sister insists on downplaying the situation, eventually she'll end up with one boy in a mental hospital, and one six feet under.

Ugh, they should handle this ASAP before something really bad happens. I should know, my older sister always hated me for being born and our parents never seeked professional help. She tried to kill me several times and almost succseded. What did my parents do? They beat the living s**t out of her wich traumatised her and made it worse but then again they abused us all.

"I should stay out of someone else's parenting". Well DOH, that's what you said. So, it's agreed by BOTH of you, you're NOT babysitting. 🤣🤣🤣. P. S. Your sister's a moron.

Big red flags there. Harley sounds like he's dangerously close to a 'narcissistic sociopath' or even a 'callous unemotional (CU)' diagnosis. What he's showing isn't just simple sibling rivalry -- it is a fundamental dislike of having their unique power and position of entitlement usurped by another. Harley's jealousy is extreme and unwarranted, and he sounds as if you can never trust him with Everest. I would get that child checked out by a special therapist dealing with this sort of pathology, because if Harley is what I suspect he is, that is called 'psychopathy' and it is non-rehabilitative, recidivist, and escalating behavior. The OP is right not to get involved in that scenario until Mom and Dad take it more seriously and get Harley help. He's volatile and if he's CU, he could seriously hurt her as well.

OP has no right to judge. True. Kind of... But she doesn't have any obligation either to put up with a problem the kids parents don't seem to be willing to solve, or even address. Absolutely NTA.

This is just not a case of a jealous older sibling. This kid needs help, and lots of it, like yesterday! He almost sounds psychopathic. A good child psychiatrist with lots of psychological testing are in order here.This is a tragedy waiting to happen.

The first thing I noticed in this post was the age gap. Unfortunately, animosity between siblings with a large age gap is common. Some grow out of it, others do not. That's just the reality. Therapy might help, but that will depend on how deep the jealousy goes. And yes, it's jealousy plain and simple. I'm the youngest with a large age gap, and it's taken years for me to realize that my sisters would have drowned me at birth given the chance with no repercussions. While they say they love me and that I'm the problem, their actions are a foghorn on blast.

Harley sounds like a psychopath in the literal clinical definition... This is very scary behaviour and what will they do when he hits puberty? That yelling and 'passive' attempts to get rid of his brother will turn a whole lot worse.

I wish someone had stepped in and forced my parents to acknowledge my older sister's abusive behaviour toward me. It started very early.

My brother and I were adopted as infants and are 21 months apart in age; we are not related to each other. He was always abusive, sometimes physically, moreso with constant bullying. I have no contact with him -- I am now 72. To call this behavior, with OP's story, "just sibling rivalry" minimizes the dangerous nature of the older boy.

The OP says the sister has been getting Harley some help but then later claims the sister is ignoring the problem. I dunno, as a parent I know it's sometimes harder to help a child with a problem than it would seem. I'd like to hear the other side, there might be missing info here. But if the sister just doesn't want to babysit for any reason she's within her rights to say no, sister can always hire someone else

Honestly, this sounds like sociopathic behavior except OP said Harley plays fine with other kids. With this kind of deep-seated hatred (this goes far beyond simple 'dislike' imo), I would not trust him to not cause purposeful harm. It's possible he already has and it's been excused as accidental. If so, it will escalate as he gets older and bolder. I hope OP keeps a close eye on things, at some point, CPS may need to be contacted. For now, both boys should be in therapy. My heart breaks for the rejection the 5 yr old is consistently getting and how that will affect him long term.

Oh my! My mum was extremely anxious and nervous, and she could not handle parenting responsibilities on her own while my dad was at work. She told me after I became an adult that the one thong she couldn't stand was me and my brother fighting when she was pregnant with my sister. She said she would sit against her and dad's bedroom door with me and my brother barricaded on the other side. Once I thought about what she said, some things occurred to me. 1. When she was pregnant, I was one and my brother was five. Who would call a five year old beating down on a one year old a fight? 2. The basement stairs were right outside my parents' first floor bedroom. 3. I finally realized why I always thought everyone was bigger than me. I will be 64 tomorrow. I have worked hard towards recovering from this and other childhood traumas, but they will always be there, even if they're much smaller now.

I think Harley is going to try to murder his brother someday if the parents keep turning a blind eye to towards his behavior.

Can we please address the elephant ... calling a child 'Everest'? This on it's own is a huge red flag.

yes I understand why she's uncomfortable. While I'm not in this situation, saying no to helping her sister & not watching her nephews also doesn't feel like the solution either. Maybe they could spend time 1x1 with each kid somehow to help the situation overall? Just seems like isolation of these two parents & the kids could further harm...isn't a family supposed to come together to all help & set an example for the younger generation?