But you have to. In many countries, the copyright sticks with the author unless there's an agreement that says otherwise. Normally, that is part of an employmen

But you have to. In many countries, the copyright sticks with the author unless there's an agreement that says otherwise. Normally, that is part of an employment or consulting agreement. Further, if he was an employee, in many countries, it's illegal to work for free or "defer" pay until there's cash in hand. And it sounds unlikely he was a contractor as there is no mention of invoicing or similar. Getting rights and responsibilities in writing protects everyone involved. And do it before cash and emotions are involved.