hello, in my point of view it's better to write an explanation letter on why it did happened. Make it informative or detailed as possible, then have it notarized. Also attached all pertinent documents that will support the facts about your explanation such as Birth Certificates of your brother and father. Make sure you'll be able to "convince" the CEM that your stating all the truth. When I submitted my full documents more than a year ago, I have so many notarized explanation letters due to some issues that I thought would affect the scrutiny process or should I say possible causes that CEM will doubt my application (e.g. my mother has no official birth certificate coz she has no records in their time since she's a product of post World War II. Her birth certificate is needed in my application because it's a support as proof of relationship with a relative, that she is the brother of my uncle who is a Canadian citizen). Hope this would help.