A friend of my you as got a 6 year old boy but is biology father leaved this mother before she had him.Know his mother been in a relationship with another bloke for 5 years and as two little girls by him he wants to adopte the little boy and bring him up as is. She is confused on where they stand with this do they have to get his father promison for him to adopte the boy or not confused

You are in the UK. Just get a lawyer and get it sorted out. Yes they have to get the fathers permission to adopt. It is legal thing and it has to dealt with through the courts in the UK.

This friend of yours adopted the little boy and now his biological Father comes back, to find he had a son. So now he wants his son back. Is that correct?

This needs to go to court. The Father can say he had no knowledge of the boy's birth. This would need to be proven. Maybe he was told and just blew it off. Maybe he was not told, the Mother believing that it was better for the child, since the Father left them both. Abandonment.

The courts could decide that the child stays where he is. To uproot the child now could be detrimental to his emotional, psychological, and physical welfare. But no one is going to know that for sure, until there is a court of law determining the outcome.

Good luck to your friend.