My kids aren’t mature to be adults

I can’t and won’t choose between my kids??

I need advise as I have been crying as I feel broken about my two oldest children.

Back story I have a son 24 who is getting married.
His sister made a bad choice last year.

She had a sport tournament booked and paid for and was cancelled due to covid. Last year it was put back on in July. All My children live and breath sport.

My son and his partner got engaged and quickly booked a venue for their engagement party. 3 weeks leading up to it my daughter was talking to me about her tournament and it clicked that it’s the same weekend as her brothers engagement.

No their is no question she made the wrong decision and went to the tournament 7 hours away. It wasn’t possible to do both.

She has tried to contact him over the last 8 months but he won’t and trashes her to everyone. I’ve tried talking to him. But very quickly he cut me too. His partner won’t respond to me. I send messages tell him I am there for him. I love him.

My hubby (not his dad) and I had to leave and go overseas to sort out his mothers estate as she died and so did his son within 6 months of each other. We have had a lot happen and family means the world to us.

I’m rambling but I’m lost.
I get messages when I try to talk to him about how I was never there for him. Never done anything for him. I was a single mother who left a narcissist with years of torment. Sadly their father has nothing to do with his daughter so him talking to our son is out of the question.

I get my son is hurt and his partner but my ex and her mother all say don’t invite her to the wedding.

There are things being said to other people on both sides. No one is innocent now. It’s just a mess

My son over the last 8 months has barely spoken and then sends me texts about how they have picked a venue and date. Messages back and forth how happy I am for them. And then the clincher he wants $10,000. I said we need to talk.

You guessed it, it didn’t end well. He’s not inviting his sister. All I said is that’s not ok. This isn’t how to deal with conflict. This will impact the rest of your life. And I got Fk you fk your money and your not invited. And then he trashed my hubby who has been there more than his dad in every way. (My son came and asked for the money to buy an engagement ring and my hubby handed him the cash he need on the spot). He paid it back over then coming months.

I have a long time till the wedding so time is on my side but I can’t stop crying. My daughter doesn’t know yet and I can’t believe they have carried this on this far.

My son said I not only have done nothing for him but that I take her side.
I’m loosing him and feel I’m grieving all over again.