How to increase keyboard light with Touch Bar not working
I don't think there's a way to manually adjust the keyboard backlight without the Touch Bar working, but you can set it to automatically turn on in low light:
Apple:

Adjust the brightness automatically
To set your keyboard brightness to
adjust automatically:

From the Apple menu, choose System Preferences,
then click Keyboard.
Select the &quot;Adjust keyboard brightness in low
light&quot; checkbox.