Yesterday I had a tearful encounter in office hours with the most avid participant in the math class I teach, in which she related the following situation.
She is an international student whose parents are well off by local standards but have made significant financial sacrifices for her to study abroad at the university where I work. Part of the plan was that she should have a scholarship, but it has recently been denied on the grounds her grades are not strong enough, and as a result she will have to switch to a nearby university in the fall. Part of why her grades aren't strong is because she is a very specifically focused student: professional mathematics is all she really wants to do with her life. She already knows. When she is able to do what she wants, she just studies math. She works extremely hard, but at end of the day she couldn't care less about her other courses and views the struggle to get good grades as a distraction from what's important to her.
Her parents disagree that there is any future in math for her. They tell her it's not worth it and that she's bad at it. They're medical doctors in a country where teachers are treated poorly, viewed as people lacking the talent to do anything better, and are worried that a career in math would be both unremunerative and undignified—which might be the case in her home country, but my student also doesn't hope to return home. Nevertheless, for because her parents are footing the bill and because she's not willing to openly defy them, my student will finish a pure CS major when she enrolls in her new university, and won't be allowed to enroll in any future math courses during undergrad.
I watched her just crumble as she told me this, weeping and apologizing for it, unable to make eye contact. She's about to embark, without any choice in the matter, on a course that's going to make her miserable for years, if not longer, and moreover, from what I know of her, she is just the kind of person who should be in math.
I've told her there's nothing anyone can do to stop her from learning on her own, and that absolutely no instructor would refuse to let her sit in on whatever math course she wants, so that at most this will be a hiccup resulting in her getting a sort of bachelor's degree she doesn't really want at the expense of what she'd rather do, and that at the time she's financially independent, she can really study what she wants, but one could tell she's not completely buying this. She's devastated, and I can hardly blame her.
What can I (or anyone) do to help in this situation?