Estranged son .

Hi I am new to this group and I hope this doesn’t all sound about money .
Two years ago we gifted a hefty deposit for our three sons to buy houses .
Shorty afterwards our youngest announced his engagement and asked for money towards the wedding . But we had no money spare to offer so explained it was not possible .
After a two year engagement and as we live more than five house drive away and Covid barely any involvement in wedding preparations , they had a huge wedding last august and announced her pregnancy too .
A month after the wedding our son messaged us saying he was having counselling for what he saw was a dysfunctional relationship with us and was cutting off all contact with us .
We sent advent gifts but had a message saying they were unwelcome and unwanted , and again he wanted NO contact.
Our grandson was born four days ago , information from our middle son , which he was told. Feel free to share with the parents .
We are totally heartbroken , we have no idea why he sees our relationship as dysfunctional.
All three boys had a normal childhood and were happy children , youngest being my favourite if truth be told , all went to university , (youngest son was always using bank of mum and dad .)
I feel it’s his adult relationship with us he finds difficult and for probably the first time declined his request for money . My other sons say he feels we were unsupportive
He is heavily influenced by her parents who live very local and see them almost daily . She says, jokingly, that he is the son her dad always wanted and her dad love him more than her .
Her father came up to me at the wedding rehearsal and said” I bet you cannot believe how much he has changed since he has known us “
I know it is only six months since his estrangement but I am really struggling .
My friends say being a father with make him see sense but I am not so sure.
Any advise would be greatly appreciated