She needs to look at the website for info based on income, etc.
https://financialaid.stanford.edu/undergrad/how/parent.html
“In cases of separation or divorce, we expect both parents to participate in paying for your education. We will compute separate contributions for your custodial and non-custodial parents.”
There’s a non-custodial parent waiver petition form, but these generally require backup proofs and the waiver is at the U’s discretion.