Final answer:
The relationship between Marty Lee and Henry cannot be determined without specific context such as the title of the book or story they are from.
Step-by-step explanation:
In order to provide an accurate main answer to the question of who Marty Lee is in relation to Henry, it is essential to have specific context, such as the title of the book or the story in which these characters exist. Without this context, giving a definitive explanation is not possible. Typically, in literature, characters' relationships are defined by their interactions and the roles they play in each other's lives, whether they are family, neighbors, or friends. A character like Marty Lee could be any of these in different stories or situations. It is crucial to look at the text where these characters are mentioned to understand their relationship.