One of my kids went to an Ivy and is now in a PhD program for music. But that route will hardly lead to a career in the music/entertainment business. The student in question could do a program in business/management or music industry but honestly, there are plenty of internships with non-profits as well as profit-making agencies that handle talent. I could list some in the areas near Cambridge but won’t for obvious reasons.
The son should look at craigslist and hireculture.org, a great site with internships and jobs in non-profits and cultural organizations of all kinds. The career office will have listings too. A degree from an Ivy opens doors (but also results in teasing, labels like “smart girl” and high expectations from employers-it’s not all golden).
Grad school is NOT necessary for these goals and getting experience in the workplace, whether paid or unpaid, is the best way to go.