apple watch not a source in sleep app

It is slightly infuriating. My wife’s watch will track steps, heart rate, location, noise for gosh sake but it will not show up as a data source for sleep.

Hi lab_goddess,

Welcome to Apple Support Communities. You can turn on Track Sleep with Apple Watch in the Health app following the steps from the Apple Support article: Track your sleep on Apple Watch and use Sleep on iPhone

Get more accurate results with your Apple Watch

If you paired your Apple Watch after completing Sleep setup, you can still turn on Track Sleep with Apple Watch. In the Watch app on your iPhone, tap the My Watch tab, then tap Sleep. Then tap Track Sleep with Apple Watch to turn on this setting. To get the most accurate results when wearing your watch to sleep:

•Turn on Charging Reminders. On your iPhone, open the Watch app and tap the My Watch tab, then tap Sleep. Tap Charging Reminders to turn on a reminder on your Apple Watch to charge before your Wind Down time. If your watch battery dies, it won't track your sleep data.

•Make sure that you're wearing your Apple Watch at a comfortable fit. If your watch is too loose, the accelerometer might register too much movement during your natural sleep.

Feel free to reach back out if you have any questions.

Best regards!