ILR Application - Child No Longer Living in Family Home

A family friend is living in the UK as a dependent of her mother, who is the spouse of a UK citizen. Both currently have FLR, so their next application will be for ILR. She is 19. Unfortunately she has fallen out with her mother, moved out of the family home and is living with her boyfriend and his family. She and her boyfriend are now talking about renting a flat together. But she is concerned about what will happen when she and her mother need to apply for ILR.

As I understand it, as she is over 18, she will need to complete her own ILR application. But I don’t think she will meet the requirements for ILR, as
(a) she is not living with her mother and stepfather, and
(b) if she and her boyfriend rented a flat, she would be regarded as living an independent life.

Furthermore, she will surely be dependent on her stepfather’s income, so she will need him to provide documents.

Is it possible for her to make a successful ILR application in these circumstances? Or does she need to mend fences with her mother and move back into the family home?

If she is leading an independent life, then her ILR application may be refused. If she chooses an independent life as you described, then it is her responsibility as an adult to figure out another way to stay in the UK rather than relying on her parents. I suggest communicating to her that this could jeopardise her status and force her out of the UK