Can armed forces member apply for his step child?

Good morning forum
Can any of the gurus please confirm whether a member of armed forces can apply for his step children's settlement visas.

He is a British citizen and a member of the armed forces. He applied for his wife and she was given 5 years leave to enter as a spouse of a member of armed forces in June 2016 until June 2021.

Can they both now jointly apply for settlement visas for her two children whom she has sole responsibility for?

Where are the children other parent?

Who is this query for? Why can't these people you are asking for register and ask their own questions?? Or are you advising people and charging a fee given the wide range of category questions you ask on the forum?

The childrens other parent, the father - is in their home country but they do not live with him.
The query is for a community member who does not speak good English, most people I help do not have even money for food to eat let alone a computer to register and ask questions, hence me assisting. I am not charging anyone anything for my assistance.

Can you advise?

Is the father named on their birth certificate?

Were the children born while the parents were married and if yes, what were the custody award for the children?

Thanks CR001

The parents were never married but the father is named on the birth certificate.
Since they separated he does not play a role
The home country is Ghana

The armed forces state a member can apply for their children but makes no mention of step children hence my question.

Can anyone please advise?
Can a member of armed forces apply for step-children's settlement visa or is it only biological children?