PR for Extended family member

Hi

I am EEA Citizen with Portuguese and British passports.

I have extended family member (my mother), currently on EEA residence card and soon she will be 5 years in UK with me.

How can I apply for her PR? what supporting documents I should include with here application

In her bank account she has little balance because I pay for all her living expenses. I have joint bank account with my wife.

Thank you
Dipesh

She need to apply using form EEA4.

Proof of your 5 years treaty rights (or PR card if you have one).
Proof of relationship (your birth certificate showing her as your mother).
Proof of 5 years of residence in the UK for her.
Passports (hers and yours).