Family members include your:
Spouse: A husband or wife of the opposite sex
Common-law partner: A person of the opposite or same sex with whom you have lived in a conjugal relationship for at least one year
Dependent children: Daughters and sons, including children adopted before the age of 18, who:
http://www.cic.gc.ca/english/applications/guides/EG79.html#wp613443上記以外の親兄弟は、移民申請にいう「family member」ではありません。