Enable USB Debugger on a phone with a broken screen
I don't think this will help, but anyway. If you could somehow execute following command on the phone, you should be able to just make it work:

setprop persist.service.adb.enable 1

This will enable USB debugging on the device and persist across reboots. The phone might need to be rooted.

Maybe connect a wireless keyboard and do some key combinations to reach command input. I have no idea how to do that though.