Hello Steve Labkoff,
Thank you for posting in Apple Support communities. We understand that you are wanting to know if your wife uses keywords for iCloud Photos does the keywords assigned update on all devices using the iCloud account. We would love to provide you support on this.
The short answer is yes it will transfer the edit.
When you are using iCloud Photos any changes that you make to any photo saved in iCloud promulgates to all devices that are signed in with the same Apple ID and has iCloud Photos turned on. So in essence if your wife makes an edit to a photo using a keyword the change will be copied by iCloud Photos and then updated on other devices.
This resource tells you a bit about iCloud Photos: Set up and use iCloud Photos
Thank you for allowing us to support you.
Have an awesome and productive day!