My grandson Harry

Tanith is correct. Harry is old enough for his views and wishes to be taken into consideration.

You say your DD has recently met her partner and is to be married soon. He will not have had time to build up a relationship with Harry, added to which Harry would have to change schools presumably part way through his GCSE years.

Why does this man think it would be better? I would be somewhat wary if he started making demands and trying to control other people's lives; after all he can scarcely know any of you well enough to judge. (But then I have never been any good at being told what I should or should not do, so other people may look at this completely differently.)

Harry is old enough for his own views to be considered , how does he feel about the situation? I don't think he could be forced to do something he doesn't want to do, have they even asked him?

There is nothing intrinsicly wonderful about living with a parent, when he has spent most of his life so far mostly with grandparents, and his sisters are living with you.

Are you officially the guardians of these grandchildren or is it an unofficial arrangement?

And does he seem a man with whom Harry could form a father-son relationship? Does he want to see more of Harry's sisters too, or is it just Harry?

I wonder why the new partner says Harry "should live with a parent" and not that he would like to have Harry to live with him and your daughter? That would be a more direct way of suggesting it.

It sounds very negative - as thought he does not think that Harry should live with you. How do you get on with him in general?