Percy Winchester?

This is a story about how the brothers have found a half brother. But it was not from there fathers side.

What happens if the fates brought back Mary Winchester so there hero of Olympus could be born.

With Mary brought back to the world she and Poseidon had Percy and with Mary having finished her purpose was sent back to heaven and her son, the little demigod sent to a woman who could see through the mist and has faced many demons in her life. A woman called sally.

This story is after heroes of Olympus series and Percy is 18. Dean is 28 and Sam is 24 this is around the time of the apocalypse so if there ages don't add up comment and I will change them. So Dean was 10 went Percy was born.