This from the bereavement fares section, but this list the "family" definition.

http://www.aircanada.ca/cargo/servic...ate.html#fares

Eligibility
Travellers eligible for Air Canada's Bereave Fares are the deceased's: spouse (includes common law as well as same sex partners), child (inludes adopted / step / grand / great grand), parent (includes step / grand / great grand / in-law / common law in-law), daughter, son, father, mother (includes legal / in-law / common law in-law), brother, sister (includes step / half / in-law / common law in-law), aunt, uncle, niece, nephew (includes those of spouse and common law spouse), legal guardian (with proof of judgement) and spouse of legal guardian . All above include in-laws of same sex partner.
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So has all of the above? I would pay anything to see someone get in using one from each category