Just another day where someone else learns an important lesson about backups.
Depending on how he’s set up his account, some of it may be in the cloud in which case it should sync back down when he sets up the new phone (or he can view it on the web as someone else suggested.
Connected to a PC, it’ll need to be unlocked. The touchscreen might still work if the display isn’t lighting up, maybe? Follow the grease-stains on the screen to enter the lock pattern, if that’s what he’s got set. Some devices require you to change the USB mode from “charging” to “file transfer” when connected to a PC, that’s going to be trickier to do blind..!