ILR for Daughter (ancestry visa dependant)

[JonBrand]

Hello,
My sister has settled here in the UK on an ancestral visa via her grandfather.
My niece, her daughter was over here with her as a dependant. My niece subsequently left the UK (personal reasons between her and my sister) to be with her father in South Africa after being her for 4 years. She still has limited leave to remain in the UK and ordinarily would be able to apply for ILR if she had stayed in the UK in the next few months.

Her Visa for the UK will expire mid this year.
The family situation has changed and she is due back to the UK. Will she be able to extend her visa or will she be able to apply for ILR at the same time as her Mother (mid this year), she will have been absent for a year in April, which would break the absence rules?
Thanks in advance for any help.