If you wish to believe this was a vision that John had about a dead person whose life had ended so be it. I believe the more likely understanding of this was about the future of His Church and the millions of souls associated with it. Maybe God has a Mary obsession too but I just don’t think that is the most likely possibility here.
Matthew 22:32
" 'I am the God of Abraham, the God of Isaac, and the God of Jacob'... He is not the God of the dead but of the living."
Mark 12:26-27
"As for the dead being raised, have you not read in the Book of Moses, in the passage about the bush, how God told him, 'I am the God of Abraham, the God of Isaac, and the God of Jacob'? He is not God of the dead but of the living. You are greatly misled."
Luke 20:37-39
"[Moses] called 'Lord' the God of Abraham, the God of Isaac, and the God of Jacob; and he is not God of the dead, but of the living, for to him all are alive." Some of the scribes said in reply, “Teacher, you have answered well."