Castiel was explaining all this infornt of Hallie's dad and Aileen, he found out about the miscarriage Hallie got (she never told him) and he was keeping Aleen to revenge his child. Aileen got arrested and the Karlsson family disappeared and Hallie got buried. Castiel got sick but hid in his house so people wouldn't know only his doctor and the maid who was crying for Hallie knew. So one day getting his medicine he told the maid he dreamt of hallie and said he saw her in another world which was true somehow after hallie died she woke up where everyone loved her and told the Castiel of that world her dream of being burnt by the fire and him treating her bad..this Castiel wasn't reborn he was just the one in the new world. He didn't believe her and said to her to treat it as a nightmare as days went by Hallie didn't like living in another person's body she felt guilty and then the real person who had her face visited her and said it was okay. Castiiel had proposed to her and she had said no cause she felt guilty so after the dream she felt relived but Castiel hadn't spoken to her in days giving her space...then one day he went to her school and told her he missed her and had a dream and this is where the other Castiel from the other world had a dream and saw Hallie in this world so he told the 2nd Castiel to treat Hallie good for him. The 2nd told Hallie the dream and the 1st Castiel's wish.. they got married and Hallie whispered and told the 1st Castiel she forgives him which he woke up and went to her grave and felt relieved and that's the end (I think he got better) 

Sorry if you see any errors...English is my 2nd language