Since she didn't sign anything she has no legal responsibility to repay the loan. That's junior's responsibility, which he has obviously disregarded.
I don't think we really know that. She gave "personal info" and may very well have agreed to be a co-signer for all we know. I agree that the very first thing I would have found out is if she had any obligation to pay. If not, then what you suggest is probably what they should have done.
Current Score: Mar 2019: EX FICO8 779, TU FICO8 800, EQ FICO 780, TU Vantage 773, EQ Vantage 786 AoOA: closed: 35 years, open: 24 years; AAoA: 11.8 years; Inquiries: 2019: 2, 2018: 3; No BK ever, 1 30 day late in 2013 Amex Gold, Amex Green, Amex Blue, Amex ED, Amex Delta Gold, Amex Hilton Surpass, BoA Platinum Plus, Chase Slate, Chase Amazon, Chase CSP, Sync Lowes, Sync JC Penney - total CL 129k Loans: Prosper (20k/3yrs 7.14%), Lending Club (10k/3yrs 5.89%), Chase car loan (35k/6yrs 0.9%)