Question

I am from Nova Scotia Canada and recently my father passed away. He has lived with his common law partner for 9 years, but is still legally married to his ex wife. I am wondering, if I, as his only living biological child can contest on the ex wife receiving the death certificate?? Also, when my father and his common law partner bought their house, the ex wife was made to sign a document and my father paid her out $1500.00. I am not sure if this document says that the ex wife cannot go after the house or if it states that she has given up all marital rights. Is it tru that after so many years of being sepperated, that the marriage is basically void? I am want to contest the death certificate as I know that the ex wife is going for my fathers CPP and widows benefits. I refuse to let the ex wife end up with this money. I am wondering if I have any rights to this pension??