Through this connection, the Dark Lord had learned more about Potter (though he never said what he learned, stating it was not his story to tell. However, he did say the teen had not known about magic until he got his Hogwarts letter). Somehow, "things" turned into Potter getting "lessons" from the Dark Lord himself. If what the elder wizard said is true, Dumbledore wasn't as focused on Potter's wellbeing as Severus had thought.