After Emma used the Cristal de Caballero to turn Philip into a human, she chose Jax to be her boyfriend over Daniel. Daniel was erased from his old life in Miami and lived in the Everglades for his whole life in this alternate reality. Emma was the only one who remembered him.
After she got Daniel to remember, she was going to turn back time to stop her mother from dying. Everyone warned her not to and why she shouldn't, and she granted Daniel's wish to go back to his alternate life instead.