MYSQL SELECT with result field containing an array from subquery

Hello,

I'm trying to make a query that's really confusing me and despite going through and reading several examples, I still can't make a query that works very well for me.
By the way, I have four tables here:

I would like to select the latest downloaded music and have information about their corresponding authors (I know how to do that very well with joins).
The problem I have lies in the structure of the database that I have and that unfortunately I cannot change. Each piece of music has an author and may or may not have a co-author.

So, I would like to make a single request where I select the last 5 music downloaded and have the name and ID of the main author of the music but also the names and ID of the co-authors if there are any.
Before, I did this operation in two stages and it worked well; but this time I want to do it all at once. Is it possible ?
Here's what my query looks like so far:

$query = "
	SELECT COUNT(dw.id_music) as occurenceValue,
	ar.id as idArtist, ar.firstName, ar.secondName,
	mu.title
	FROM download dw
	INNER JOIN music mu
	ON mu.id = dw.id_music
	INNER JOIN artist ar 
	ON ar.id = mu.artist_id
	WHERE dw.d_date >= ?
	GROUP BY dw.id_music 
	ORDER BY occurenceValue DESC
	LIMIT 5
";

I would like to get a result like:

array (
	array (
		'id'=>1,	
		'title'=>'Stay with me',
		'id_author'=>5,
		'name_author'=>'Mike Five',	
		'co-authors'=>array('6'=>'Emmy Six', '4'=>'Jennifer Four'),
		'downloads'=>3
	),
	array (
		'id'=>4,	
		'title'=>'Astronomia 4k',
		'id_author'=>3,
		'name_author'=>'Sandra Three',	
		'co-authors'=>array('6'=>'Emmy Six', '2'=>'Peter Two'),
		'downloads'=>2
	),
	array (
		'id'=>5,	
		'title'=>'In the jungle',
		'id_author'=>1,
		'name_author'=>'John One',	
		'co-authors'=>array(),
		'downloads'=>2
	),
	array (
		'id'=>6,	
		'title'=>'Stay with me',
		'id_author'=>1,
		'name_author'=>'John One',	
		'co-authors'=>array(),
		'downloads'=>2
	),
	array (
		'id'=>2,	
		'title'=>'Stay with me',
		'id_author'=>1,
		'name_author'=>'John One',	
		'co-authors'=>array('3'=>'Sandra Three'),
		'downloads'=>1
	)	
)

Would you help me please?