Shut the computer off at 5pm. It's pretty simple. I've also stopped accepting the 8 AM meeting requests that get fired off at 3 AM same-day from the subcontine

Shut the computer off at 5pm. It's pretty simple. I've also stopped accepting the 8 AM meeting requests that get fired off at 3 AM same-day from the subcontinent. It takes some resetting of expectations, but it's a far healthier and more professional set of ground rules.