New baby

So what happens now is that the father and mother of the baby work on a custody agreement + child support and they establish a new normal

We don't know anymore as to what was posted. As we don't live in the same town. Yes I would like to ask all those questions too. Daughter is devastated as they live very near and isn't allowed contact. From what I can gather he is at home with his parents. And she and baby in the flat that belongs to our daughter and son in law. We haven't even see the baby yet as we aren't allowed to travel out of our area.

'Without any explanation'? I don't think they have to explain themselves. It's their lives - and their business. People who get together as teenagers often grow apart.

Be very careful, though, not to take sides, or badmouth anyone, just in case they get back together!

I'm so sorry. These things happen but it is of no consolation to you.
Do/did they live with your daughter or just rent the flat from her?
Your grandson has left? Or is he still there? It isn't really clear.
What is your daughter planning to do?It must be very upsetting for her too.
All you can do is support your daughter and grandson and encourage him to keep up contact for the baby's sake.
One thing many people don't realise is registering a baby can get delayed during Covid- but it is important his name is on there if he wants contact with the baby.
Is there any chance mum may have PND as well? It is very early days in the baby's life so maybe if you all work together things will sort out for all concerned. I hope so.

So sorry your grandson and partner have split. You must be devastated. I can sympathise as my daughter has discovered she is pregnant and her husband just walked out after many months of arguments because of his depression.
Hope the child's parents can sort themselves out after a break. It's never fair to split so soon but just have to cross fingers that they see sense. It's heartbreaking.

Sit tight, offer support if asked for, unless there is some really valid reason, leave it for them to sort out. It must be very hard you, and you do have my sympathy, but you really are in a no win situation. What is accepted now as loving advice can be misconstrued as interference in the future. I do hope everything works out for you.