If you study Blake you will soon find that he uses the word ‘Death’ in many different ways. He used the most common use, the end of physical life in his earliest works. But in his mature thought and poetry he turned the idea on its head:
Physical birth was expressed as Eternal Death or wherever we find some one leaving Eternity for the world.
In the Book of Milton Blake wrote that Milton was walking among the 'Eternals', but when he heard the Bard's Song,
"Then Milton rose up from the heavens of Albion ardorous!
The whole Assembly wept prophetic, seeing in Miltons face
And in his lineaments divine the shades of Death & Ulro
He took off the robe of the promise, & ungirded himself from the oath of God
And Milton said, I go to Eternal Death! The Nations still
Follow after the detestable Gods of Priam; in pomp
Of warlike selfhood, contradicting and blaspheming.
When will the Resurrection come; to deliver the sleeping body
From corruptibility: O when Lord Jesus wilt thou come?
Tarry no longer; for my soul lies at the gates of death.
I will arise and look forth for the morning of the grave.
I will go down to the sepulcher to see if morning breaks!
I will go down to self annihilation and eternal death,
Lest the Last Judgment come & find me unannihilate
And I be siez'd & giv'n into the hands of my own Selfhood.
The Lamb of God is seen thro' mists & shadows, hov'ring
Over the sepulchers in clouds of Jehovah & winds of Elohim
A disk of blood, distant; & heav'ns & earth's roll dark between
What do I here before thè Judgment? without my Emanation?
Speaking of Blake's physical death we have a record of it in Poet's Graves:
"Bake died in poverty in 1827 in a room in Fountains Court (off The Strand). It is reported that on the afternoon of his death Blake burst out singing due to the joy of the things he saw in heaven."
In some cultures lamentation at a funeral is not found; instead people are expected to rejoice in a kind of testimonial that a person's physical death is not the end, but a new beginning. That was certainly Blake's faith.
A young man at his father's funeral gave directions to the organist for several hymns with a spritely tempo. In spite of specific orders she played "Holy holy holy" etc. That demonstrated a clash of cultural values. Blake also (rather continuously) clashed with his contemporaries.