Child entry clearance

Hi all,

A mother currently has limited leave to remain in the UK under the Immigration Rules on the parent's 10-year route to settlement because it would not be reasonable to expect her child to leave the UK.

She has another child abroad from a previous relationship for whom she has sole responsibility as the father has not been in their lives since the child's birth, is it possible to bring that child to the UK under any route?

Thanks in advance

following from the above post, the online application form on GOV UK states that a child can apply to enter the UK if they are a:

Non-British child of a parent who has or is applying for permission to enter or stay in the UK as a parent - a parent who has or is applying for permission to enter or stay in the UK as the parent of a child who is a British citizen, settled in the UK or is a specified EEA national with permission to stay in the UK under Appendix EU of the Rules.

The parent has limited leave to remain as a parent on the 10-year parent route because she has a child born in the UK who has lived here for over 7 years, and it would not be reasonable for her to leave the UK. The child's father also has ILR since 2017 after the child's birth, but she has not applied for British citizenship.

Does the above guidance mean that the child has apply for BC before the parent's other child from a previous relationship can join her in the UK or can he apply to join as of the current situation.