@Hopeful I loved your explanation.It does make sense with all that imagery.
And it was released as a tribute on 3rd anniversary of his grandma's passing,it seems.
So,he was indeed talking to her in that song and saying that she sleeps peacefully.
I think he finally made peace with the guilt of sacrificing her.(some may not agree with this sacrifice part).
And the part where everything is shown backwards may represent the desire to turn back time,you know like how superman undoes his dear ones' death in the movie.
However,nothing with these occultists could be so straightforward.So,I looked into the symbolism and found this.
Parrots symbolise fire and Sun in Mayan civilisation and believed to play a role in Mayan creation myth.They also symbolise fertility in many religions,hence,revered in occult circles.
Blue colour symbolises Egyptian God Osiris,who is believed to be the other name for baphomet/pan/lucifer/satan.
Osiris is depicted to have blue skin to represent the colour of the dead.Blue also represents egyptian goddess of fertility,Hathor and egyptian god of creation,Amun.So,mention of se* rituals.
There is a mention of flying like a blue parrot in the song.It is a reference to horus,who is believed to fly to and from sun god with info.
I do agree that the mention of winterbear could be a reference to the dead.And,in osiris myth,he is killed by his brother.While some stories say that he came back to life,others say that he remained dead.
So,in another interpretation,tea is singing the song to osiris/lucifer saying that when the devil is around,he doesn't have any bad time anymore.This kind of lyrics is commonly seen in many artists' work to show that they don't regret about the deal.
Not a surprise because when they sing about a girl,it is usually about lucifer/lucy.
You are welcome to have your own interpretation of this.