How To Write A Letter When A Patient Cannot Fly . Here is an example of a rare disease for which a patient needs a rare medicine. The letter should be courteous and polite because the consumer is asking for help and shouldn’t use a demanding tone. Reasonable ADA from www.bizzlibrary.com Or hematologist will have their own version of this letter. The doctor’s letter must contain the patient’s name clearly and other essential things that make it valuable. The letter should include a few financial details such as the consumer’s source of income and the monthly amount they pay on any large debt such as a home mortgage.