Personally, I think if she has the talent and endurance for it, she should go for Math. She will easily be able to pivot to the other fields you mentioned and she will be prepared for quant or other financial fields etc.
On CS; my daughter just graduated this year with a degree in computer science from a fairly well regarded university. She wanted to do this from high school, partly because her parents and many family members are in the industry and also because her generation have thoroughly internalized the idea that arts/humanities are a pathway to nothing more than a career at Starbucks. They are also well aware of the student loan crisis.
Yet the number of girls who graduated with her was only about 2/3 of the number who entered the program. It’s not from lack of support. As soon as her high school realized they had a potential “Woman in STEM” they went into overdrive with activities and events to the point where I joked we should get a restraining order against her guidance counselor. Colleges also strive to be “supportive” and “welcoming”. But what I kept hearing from my daughter and her friends was that the vibe in the computer science department (sex ratio about 4:1 male) was “weird” and “creepy” None of them said they had been harassed or singled out or anything major like that, they just felt out of sorts and this was a factor in switching majors for some of them. It’s rather unfair; I’ve met some of those boys and let me just say the patriarchy is in big trouble if this is its’ future. They were unabashedly nerdy though. If your friend’s daughter is a normal American girl and not willing to learn new operating systems for fun, talk about bitcoin or find continuity errors in anime series etc. she may feel uncomfortable or lonely. Of course she can socialize outside the department in that case but it’s something to consider.
Anyway that’s my 2 cents. I wish her the best of luck.
