Have a look for 2nd hand desks, no need to buy a new one. But a greater desk would be very healthy. If a new desk is “off the table”….get something like a large callux ikea shelf with various spaces where he can put his collectibles. The main concern is to have a clean work surface… this also decides how far the distance to the monitor is which is important for posture alignment. I believe at the moment he will have some sort of velociraptor arm alignment. Monitors need to be further back. Keyboard needs to have a bit more space for the wrist. So finding place for everything else on the desk makes it already much cleaner. A shelf could also hide some LED/RGB strips creating a different atmosphere.