1. They do not have any right to request anyone elses info.
2. She of course should be treated on her own merits.
Given that she has good form with lender , if declined she can appeal and see what response.
As I see it , lender (if declined) has effectively said she ain,t creditworthy for sum asked for and you ain,t any help !
You and her can rightly claim, Mr Lender has created (family) hassle !by trying to tie you in.
At best poor practise.
If she gets loan , suggest let it go .