An award ticket is valid for 1 year*, starting from its date of issue. Past that time, Miles cannot be refunded.
* This does not include exceptions like promotional offers or local deals in specific countries or regions.
You can use your Miles to book a flight for a third person, even if he or she isn't a Flying Blue member and you won't be traveling with them.
Simply make sure to enter all of their information as it appears in their passport.