IN IMM 0008 Application For Permanent Residence In Canada, you fill nothing for family if you are not married. The Family as defined by Canada for purpose of this form is
Spouse
Common Law partner
Dependent Children
Dependent child of Dependent Children
Please check page 23 of instruction guide
http://www.cic.gc.ca/english/pdf/kits/guides/EG7.pdf
Your parents, brothers and sister will be mentioned in additional family details form
Do not leave any blank fields just write N/A in fields where you are not including any family members in point 21