The apocalypse is abolished
"What happens when an angel dies?" asked Dean thoughtfully, "I mean what do they see for all eternity?"
God looked at him.
"If it is a good angel, they will see pure white and I will resurrect them. If they are bad angels, like Zachariah, they will be enveloped in dark silence."
Dean whistled a long drone tune and looked at Cas, who was looking highly uncomfortable.
"I just killed another soul." he whispered sadly, his eyes never leaving the floor.
God heard him and offered comfort.
"Son, you did as I commanded - you should not feel guilty."
Cas nodded, but his guilt did not ease.
God watched him intently as he read his mind.
"Son - Zachariah would've killed both Sam and Dean, and caused the death of millions of others - wouldn't't that guilt be even greater than the guilt you feel now?"
Castiel hadn't thought of it that way and smiled, his guilt finally lifting.
Satisfied, God then turned to the host of heaven.
"Everyone who doubted me when they heard of my death, speak up now and your punishment will not be as great."
Several angels owned up, and some were truly ashamed and sorry.
God forgave those few and they were bless again with much relief.
The others were not sorry and were sent packing to the pit to see the suffering they helped cause.
Then God turned to the angels who had not owned up.
He banished most of them, but saw the rest were truly sorry but had been to scared to admit their wrongdoing. They were forgiven and were hugged by God's grace again. Heaven was pure once more.
As a final word, God said;
"All of the demons have been killed, so there is to be no more suffering in the world unless deserved or inflicted by the humans themselves.
"Now Sam and Dean - go home and have that 'apple pie family' you have always dreamed about - of course, Castiel will be your guarian angel and friend until the day you are laid to rest, and all of eternity after that. Good day, my sons."
With that, Sam, Dean and Castiel found themselves at Bobby's house again, all three grinning like children - children who had been refilled with the love of God and true faith and happiness.