I read this and it made my ears prick up (or eyes widen, whatever the reading equivalent is), and I felt I needed to comment.
I think we can both agree that He, God, is God of the living, not of the dead (Luke 20:38), right? And for to Him,
all are alive, right? And I think we can both agree that at death, the body dies but the soul/spirit lives on, right? So there is life after death, albeit in a different manner (“It’s life, Jim, but not as we know it”

).
In the Old Testament (this is relevant since we’re talking about “praying to the dead”) necromancy is forbidden, i.e. conjuring the dead to commune or attempt dialogue with the deceased. The Lord, in 1 Samuel 28:3-25, abandons King Saul (in disguise) because he has consulted the witch of Endor to commune with the prophet Samuel. God was angry at at King Saul because he failed to wait upon the Lord as God told him to. Now, when Catholics pray to the saints, we’re not actually attempting dialogue with them or expecting them to speak back; we’re simply asking them to pray for us because they are close to God; they intercede for us; all supplications are put to God.
In light of that: in Mark 15:34-36, as Jesus is hanging on the crucifix, he cries out to God, “Eloi, Eloi, lema sabachthani?” which is translated to, “My God, my God, why have you forsaken me?” but the bystanders mishear what Jesus uttered and believed he was crying out to Elijah:
“One of them ran, soaked a sponge with wine, put it on a reed, and gave it to him to drink, saying, ‘Wait, let us see if Elijah comes to take him down.’” (v36)
Don’t you think it’s strange, based on what they [mistakenly] heard, that instead of condemning Jesus for attempting to “commune with the dead” by calling out to Elijah, they waited to see if Elijah would actually come and take him down from the cross? Yes, Jesus calls out to his Father, but the bystanders don’t hear it that way.
Why didn’t the bystanders rebuke Jesus for the sin of necromancy if he was calling out to a “dead guy”?