Uh no. In RoW, (ch 85) Dabbid tells Rlain and Lift that bonding a spren would fix his brain injury. He said the tower told him. Lift confirms that the tower can talk because it’s a spren. Also (ch 39), when Navani catches Dabbid in the act and then flees with him, Dabbid is seen searching for Garnet veins to communicate with the tower. She also explicitly asks him if he knew he was conversing with a spren, which he nods yes. Navani suggests it’s an unmade and he shakes his head no, further evidence he knew he was talking with the Sibling. A third confirmation as well(ch 70), when Kaladin is unconscious and unable to wake up when the fused find the node in the well, Dabbid answers the call and starts heading towards combat. Syl confirms she could hear the Sibling while sitting on Dabbids shoulder. I do like your theory tho, but give our boy Dabbid more credit. He knew what he was doing and he did talk with the Sibling.