Thole is a leshy, one of the tall, still, moss-shouldered forest-guardians who stand at the edges of things and keep watch. He keeps the Tall Window, the single high shaft in the Sanctum where surface weather shows, and he has stood beside it, patient and upright, for longer than most of the caverns have had names. His name is an old word for endurance, and he lives up to it without effort.
He trusts cypress because it is the tree that does what he does: stands tall, stays put, endures the seasons, and witnesses the comings and goings without needing to comment. He and the tree are the same profession.
He has watched Surfacefolk arrive at the window in the middle of one hard passage or another, and stand there thinking. He never interrupts. He simply stands with them, tall and green and enduring, and has noticed it seems to help, being kept company by something that has plainly got through worse and is still standing.
Stands witness at the window and never once interrupts; finds this is usually the help required.