US death certificate as primary document?

So far, I have no primary documents for my G0. There were 2 published books written, 1 from his county and 1 about his family, showing he was born and who his parents are, but nothing from the Canadian government (eg birth records or census) showing he was born there. (I do have a ton of secondary documents listing his birthplace, like US census, marriage record, death certificate, obituary, etc.)

However, I do have a LOT on his parents in Canada (baptism records, marriage records, decades of census, etc.). So I am considering making them my G0.

So my question is: if my current G0's US death certificate is not enough to prove Canadian citizenship on its own, is it at least enough to prove that he is the son of his parents? So I can show no breakage in that chain of lineage?

Thank you for any help you can provide!