Google’s version of Apple’s Find My Friend is Google Location Sharing. You can set this up to share your location with friends for a limited amount of time, or you can set it to always share your location with family (or friends). This helps them know where you are and hopefully make sure everyone is safe.
It works on Android and iOS, though on iOS, you need to allow Google to have background access to location services. Otherwise, the location updates will only be since you last opened a Google App on iOS.
I have not experienced any additional battery drain. If you use Google Location History, it is already saving and reporting your location to Google. So, this is just allowing your family member to view you using data your phone is already reporting.
In my usage, updates are between 2-30 minutes, but you can always ask it to refresh, which seems to pull a newer location, but I am not sure what it is exactly doing.
What are the alternatives? The best would be Glympse, which has more features for short-term sharing. It lets you pick a destination, showing your friend where you were, where you are going, and the ETA to get there.