Can we any of us imagine how it would be if on a 2nd marriage our DF was to tell us that our child from the 1st marriage was not to come to the wedding?
All of us would see that bloody great big red flag for what it is and tell DF to sling it.
There is no difference here, this bloke is letting his flesh and blood, his first born son down. Again and again and again.
I'd be talking to the entire family and instigating a boycott, that if his DS is not attending that not one member of the family will have anything to do with either of them.
Also as this deadbeats parents, I'd be straight round to the pair of them and read the pair of them the riot act.
They don't have the right to deny a boy his father.
This brother needs telling to find his balls and tell her that his son is non-negotiable and if she doesn't like it she can piss off.
My Dad's wife kicked up a fuss whenever he wanted to see us, we were 16 and 14. I don't think that much of him tbh.
LOVING the Disneyland idea!
Your mum is a legend OP.