In 5x12 Ben told Danielle to not look for him and to not follow him, so it's obvious that Danielle didn't interrogate him for the safe of herself.
She interogated Sayid because she thought he was an other and thought the others took Alex. Why did she not interogate Henry herself, as it seems her sole purpose on life, being on the island for 16 years and all, would be to find Alex.
