He could make a non-free (i.e., violating the four free software freedoms), non-OSI approved open source licence that does this, but it wouldn't be as permissiv

He could make a non-free (i.e., violating the four free software freedoms), non-OSI approved open source licence that does this, but it wouldn't be as permissive as you would probably want it to be, and it wouldn't be compatible with licences that are.