If you just got volunteered for this , I'd contact the school or whoever volunteered you and explain what is going on and tell them it is beyond your scope of "helping".

The school needs to know her mind set, I'm sure they have someone who can talk with her and help her with her problems.

I think a step back from this , and pass her on to the school assessment/counseling team.

maybe she is not mean to be studying that line of courses.

..or just something is not a fit for her.