AWS Cloudformation: Callback only for CREATE_COMPLETE or CREATE_FAILED of entire stack
I believe, alternatively, you could use CloudTrail+CloudWatch rules, but then you will get CREATE_STACK events for all stacks
Here is some information about that:

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/cfn-api-logging-cloudtrail.html
https://docs.aws.amazon.com/AmazonCloudWatch/latest/events/EventTypes.html

And, of course, there's the option to put a lambda which listens on the notification topic and filters the needed events before sending the email.