'AITA for telling my sister that people tried to warn her about her son and stepson?'

"AITA for telling my sister that people warned her about her son and stepson?"

My sister has been married for 5 years. She has a 17-year-old son and a 17-year-old stepson in her home. The boys have known each other since kindergarten, and they have never gotten along.

I remember my sister telling the rest of the family that she was called in and asked if she'd object to her son and "the other child" being buddied for a few weeks so they could work out their issues. My sister said that was fine. They tried for 7 weeks or something like that.

They were seat pals, each other's helper, and were given small "jobs" to do together to build a better dynamic, but it failed. The whole time they were next to each other, it was hell in the class. This dynamic did not let up. The two of them do not like each other; I personally believe they truly hate each other.

Then my sister and her husband started a relationship. Prior to them moving in together and also prior to the wedding, many of us spoke to my sister about what a bad idea it seemed to be because the boys were not capable of getting along.

She told us they'd have to once they were family and that it would do them some good. I asked her if she really believed that and if she really wanted to live in a house where two members did not want to see each other ever.

She told me she loved her husband (then fiancé) too much to end things or hold off on marriage. She also told me she was going to convince her son to give her stepson a chance to be a friend, if nothing else.

She said that the kids clashed in personality but had some shared interests, so they could work it out. She didn't like when our dad took her aside before the wedding and warned her it would end badly because of the boys.

My sister and her husband have a son together now. He's also caught in the middle of both of his half-brothers hating each other. We all have witnessed just how much these two do not want to be near each other. We witnessed fights, glares, all kinds of things. My sister's stepson lost his temper with our great aunt for calling them brothers.

There was an incident a couple of weeks ago. My nephew lost a friend. He had been sick for a while and sadly passed away just before his 17th birthday. My sister and her husband wanted all four of them to attend the funeral. Her stepson didn't want to go, said he didn't want to support my nephew, and didn't care.

He thought it was funny as hell how upset my nephew was and said he hated the dead kid too. While at the funeral, my sister and her husband were sympathizing with the boy's parents and expressed that both nephew and step-nephew said kind things about their son.

They told my sister and her husband there was no way step-nephew said kind things about their son and he shouldn't have been there. My sister said it was humiliating to realize other people were so aware of the bad blood.

She then said we never warned her, and I corrected her and said we did, but she didn't listen. She told me we didn't try hard enough and how dare I say we did enough. AITA?

OP responded to some comments:

Dark54g says:

NTA. I am surprised one of these boys hasn’t gone to live with other relatives.

OP responded:

It's not that simple to do. Especially when they are with their only involved parent.

Dark54g responded:

I meant you or the grandparents.

OP responded:

I know. But it's not easy for extended family to get custody. It's next to impossible. Only the other parent would have some chance.

DuckOpen says:

Your sister is delusional…the boys have not liked each other since KINDERGARTEN!

OP responded:

Yep. And in kindergarten the teacher was unsuccessful in helping them get along.

Appropriate-Royal-17 says:

Did your sister truly believe that no one outside of the family knew? Also, is your sister always this accountability avoidant?

OP says:

Not usually but with this she has been 100% each step of the way. Also, she knew the boys friends knew. There's bad blood there as a result. But the other parents and people outside that, she figured had no idea.

What do you think?