A child custody letter should include information explaining to a judge how the chosen guardian can provide care that is in the best interest of the child, according to Nolo. In the case of conflicting guardianship claims, a child custody letter should explain why one choice of guardian is preferential to the other.
According to Nolo, the judge granting the custody may consider the preferences of the child when assigning custody if the child is old enough to express such a preference. In these cases, a child custody letter should detail how the guardian choice compares to the child's preference. Nolo also suggests including how the proposed guardian can best provide continuity of care for the child for maximum stability. The letter must detail how the custody arrangement meets the needs of the child, including special needs. In determining custody, a judge may look at the current relationship between the child and custodian, so letters should detail interactions between the two.
Nolo recommends the letter include proof of the moral fitness of the proposed guardian. In the case of conflicting claims of guardianship, the letter should seek to prove the relative unfitness of the opposing claimant, such as detailing past instance of substance abuse, child abuse or mental illness. For guardians with a nontraditional family structure, the letter should also explain to the judge how the family meets the same needs of the child as families with a traditional structure.