In the book, David received help from several people but I think the three whose help had the most impact were his open-minded Uncle Axel, his sister Petra and Michael. After Uncle Axel found David speaking to what appeared to be nobody, David told him of his capability. Axel immediately realized that David had a gift which would spell trouble for him were anyone to find out. He therefore cautioned David not to tell a soul about his gift and to refrain from speaking aloud when communicating with others as this would put him at risk. It was through Axel’s counsel that David learnt that his power, just like Sophie’s six toes, was abnormal and he reached out to the other telepathic individuals to alert them of the danger they faced if they were to be discovered. David and the rest find a way to keep their gift secret.
After some of the chrysalids were captured, David, Petra and Rosalind escaped. Michael became very helpful during their escape into the Fringes land. He posed as one of the people seeking out David and the others while he was actually telepathically communicating with them enabling their escape and misleading the search team.
Petra is the third person who was very helpful. Her extraordinary telepathic abilities enabled her communicate with a woman from Sealand. It was through this communication that help was sent and an aircraft arrived just in time to save David and his loved ones. They were taken to Sealand where David got to experience the things he saw in his dreams.