I responded at length in your other thread. Please read the Double Degree Dilemma in the Read Me thread posted at the top of this music major forum.
For a double major it is one degree, not two BA’s.
When there is more than one degree, it is a dual degree. I know it is confusing.
As I wrote in the other thread, after reading several posts by you, I don’t think a double major (stressful, might take longer than 4 years) OR a double degree (5 years, more cost) would work best for you.
It seems best for you to consider 1) majoring in science and continuing music with lessons and EC performance or 2) majoring in music and squeezing in science classes for med school prereq’s during college or in a post-bacc program
Science undergrads don’t have great job prospects generally. Music majors, like any other major, have access to grad and professional schools (med, law, business, nursing etc.). You would have access to jobs outside of music, especially if you work, volunteer or intern during college. But if your family wants a “backup” major, and you like science, fine, you can major in a science and continue to develop your music. I would encourage you to do whatever you love. The finances won’t be that different.