Islamic Interpretation of Dreams (Ibn-i Sirin):
(Cheerfulness; Lightheartedness) In a dream, blithe signifies comfort, a good spirit and particularly for a grateful person.
This also applies for seeing a deceased person in a state of cheerfulness.
A blithely person in a dream is one who is grateful for the blessings endowed upon him by God Almighty of having a family, love, affection and for the ability to do good deeds.
If one is expecting a promise to be fulfilled, then blithe in a dream implies the satisfaction of his aspirations.