According to LegalZoom, a reference letter for child custody should contain information on why a possible custodian is suited to act in the best interests of the child. Reference letters may cite a person's morality, character and personal abilities.
LegalZoom states that reference letters for child custody should be written in informal language with a focus on conciseness. The writer should explain his relationship with the parent, and include any professional credentials relevant to the court. Suggestions for letter contents include personal anecdotes, descriptions of positive character traits and evidence of a good parent-child relationship. Letters are frequently written by neighbors, teachers and colleagues.