Does Billie Eilish's brother wrote her songs?

Related questions

1. Is Finneas Billie Eilish's brother?
2. Is Billie Eilish real name?
3. Why is Billie Eilish's last name Eilish?
4. What does popped a Xan mean?
5. Does Billie Eilish's brother perform with her?
6. Who died Billie Eilish?
7. What is the full name of Billie Eilish?
8. What is Billie short for?

Tags

1. #industry
2. #formidable
3. #connell
4. #billie
5. #revelry
6. #middle
7. #names
8. #steps
9. #raised
10. #actor
11. #eilish
12. #brother
13. #parents
14. #finneas
15. #musician
16. #become
17. #music
18. #sibling
19. #writer