Dear
@ abcpunjab
@ maina
The point is to prove your relationship with the person who is in Canada.
I used my birth certificate on which I have my father's name because my father had no birth certificate I gave them my father's passport copy and also my uncles' passport copy showing the same father and mother name on it to prove they are brothers.
Also I attached my parents marriage certificate and my uncles marriage certificate, both of these documents had their parents name on it.
I also explained the relationship by drawing the linage with a chart that how me and my uncle are connected.
However we all might have different relationships to prove hence use your common sense to achieve this goal.