Resurrection
It was quite a lot of information for Damon to take in, no, it was more shocking the events that took place while he was captured by Christopher and after his supposed death.
After he left his place to go find Nessa by instinct alone, his parents noticed his disappearance was abnormal and commenced a search immediately. Then comes Nessa's mother, Jenny, reporting the chances of her daughter getting kidnapped, thus confirming his report in the first place.
This led to his parents getting the military involved with their influence plus the fact the evidence was piling up. They began to track Damon down and finally found his last whereabouts.