Backlight stopped working on XZ1 Compact

My beloved XZ1 Compact suddenly, in the middle of the day, had the backlight go out. I can only see the display in bright sunlight. My husband is great at repairing phone issues but this has him stumped. Has anyone done this successfully and can give some advice? I can’t find anyone to repair and it’s out of warranty. There’s no phone out there now quite like this and now, 2 years later, buying another one would cost $200 more than what I spent originally on a new one in 2018!