If she shares her location with you, you should be able to use "Find My" to locate the devices.
Find people and share your location with Find My - Apple Support
The other way is to use Family Sharing and appoint yourself as the Family Organizer. With Family Sharing, you and up to five other family members can share access to amazing Apple services like iCloud+, Apple Music, Apple TV+, Apple Fitness+, Apple News+, and Apple Arcade. Your group can also share iTunes, Apple Books, and App Store purchases. You can even help locate each other’s missing devices.
What is Family Sharing? - Apple Support
Set up Family Sharing - Apple Support
Either way she will have to "opt-in."