Question about uploading rights

Hello. I would like to get advice from you. If not difficult. Please.
The question is:
A good friend of mine for a long time writing music. A long time ago. He is a composer like me, but he`s 56 years old. He decided to try AJ as a source of income. But he does not understand in the technical part. And he does not want to understand it. He asked me about the service.

  1. Can I put his tracks on my page?
  2. Many of his tracks are on the Internet. And their can be downloaded by any person.

It depends.

If he owns the copyright - you could manage his account/profile as a partner but if he owns the copyright then you need to be careful in case some thing were to go wrong.

When you days it’s on the Internet and can be downloaded by anyone do you mean purchased or free download?

If it’s free then why is someone going to pay to buy it here? If it’s paid for then you either need to remove it first or operate as a non exclusive author.