To think my daughter shouldn't do this?

Apologies Nannyone.
It seems that you have taken on-board the advice you asked for.
I hope everything will work out well for all.

Your daughter should do what she wants. The younger children seem ok with it. The eldest boy is old enough to move out anyway if that is what he wants to do. He sounds very selfish to not want his Mum to be happy and very rude to have ignored her friend for 5 years. I would not have put up with that behaviour from the start. He sounds like a tyrant and a bully, trying to blackmail his Mother into doing as he says. Let him leave! His loss!

What a selfish, and ignorant brat the 22 year old appears to be.
As he has been like this since day one you couldn't put his behaviour down to worrying about his mothers financial stability as others have suggested.
A mother should always look after her children's needs has also been suggested, a view I agree with entirely, but a 22 year old child?
Admittedly he is still acting like a child, but I would think that in any other family a 22 year old would be classed as an adult!
I am also more than disappointed with the grandma's comments, angry at her daughter for grabbing a slice of happiness.
Try showing compassion.
I think an excellent solution would be for the 22 year old to move in with his grandma.

Nanny one, doesn't your daughters happiness count fir anything. Let your grandson move in with you, he can sulk in peace then.

Just saying ... If I were Nannyone I would have abandoned this thread long ago. So many posters have been rude / unpleasant about her GS. She sought advice and support - clearly trying to work through a complex situation in her own mind. I think she will have felt bruised by the 'tuppence' worth that many have freely given.

This often seems to be the case on this forum ... perhaps it should be renamed 'Post at your peril ...' Not for the faint-hearted.

Some people seem to have so little understanding of people. Your GS was 14 when his father left and probably his mum was in a bad way at least for some time. He would have witnessed this as no-one else would. You have said his father was awful to him. He is obviously deeply distrustful of men and protective towards his mother. It isn't being horrible, it is expressing your concerns in the wrong way. Could you talk to him, explain that being hurt is part of life and there is no reason why this relationship should damage his mother like her previous one did. You might also point out that if he does it in the way he proposes, his moving out could upset his mum almost as much. Ask him to try staying but if he has to move out to do so quietly and without blaming his mum.

Much better if he does move out and move in with Nannyone and everyone will be happy do you have room for him Nannyone ? it's not excusable at 22 to dictate about his mums life he's been off living his own life at uni I bet he's not been too worried about his mum whilst there, now he's come back he's expecting to be in charge, no, sorry grandson, it doesn't work like that