Does LC write ALL the music?

HI,

I have been listening to LC since the 60s with a big break. Now 80% of my listening is LC.
I have been trying to find out if LC writes all the musical parts for his songs? I know on tour and live albums there are many gifted musicians that play with him. Are they playing his parts or does he have collaborators for the music as well as the lyrics?Another quick question. In the studio, does LC play various intruments and then mix or does he use studio musicians?Doesn’t really matter to me, I love his music, just curious.

Please help.

I did not find the right solution from the internet.

References:
https://www.leonardcohenforum.com/viewtopic.php?t=36306
Learning Management System Example

Thanks!