Heloise had fallen asleep, while Tyler remained deep in thought.
He made an initial hypothesis: if the "Heavenly Ghost" was the one who killed him, it could be inferred that there was a rift in the relationship between the Earthly Ghost and the Heavenly Ghost.
At the very least, they were in a competitive relationship.
Based on this inference, the Heavenly Ghost had a reason to attack Tyler using the Parasitic Blood Serpent. Flying creatures were significantly more threatening than serpents.
However, if the Heavenly Ghost could do this, the Earthly Ghost could similarly deploy other suicide attackers to target Tyler, instead of focusing solely on Heloise.
Yet, when Tyler communicated with the Earthly Ghost tonight, he did not detect any such thoughts in his mind.
.
This meant that it wasn't that the Earthly Ghost didn't want to, but that he couldn't.
.