Want to join my British child in the UK

[Summy]

Dear all,

I have a brother who is currently in Nigeria and has a British citizen 3 years old child in the Uk.
He has never visited the Uk before. Met the child's mother in Nigera but she is also a British Citizen.
The child and the mum are currently in the Uk. They are both not in a relationship anymore, but in good talking terms. The Mother took the child to visit the father when he was about 2 years old. He paid for the tickets.The child has his father's surname on his passport.He support the child's mum financially and in regular contact with them.

He would like to move to the UK in order to have a part in his child's life.. the ex is also in support of this.
Please what is the first step. Go through a migration lawyer?
He will be staying with me initially until he gets his footing and move closer to the child.

Thank you for your help.

[CR001]

https://www.gov.uk/uk-family-visa/parent

[Summy]

Thank you very much for your response.

Do we need to get a letter from the child's mum, stating that he is active in the child's life. Would that be ok?Or Must he get one from the court.

[Summy]

https://www.gov.uk/uk-family-visa/parent

Thank you very much for your response.

Do we need to get a letter from the child's mum, stating that he is active in the child's life. Would that be ok?Or Must he get one from the court.