LOCATION: Canada Rights of biological siblings when an adopted child passes away without a will.

My friend's mother passed away recently without a will. My friend is her only surviving family member and her daughter. When she went to speak to a lawyer regarding the estate. The lawyer requested she make a family tree of her moms biological siblings because they may be entitled to some money. I was undr the impression that the adoption would have invalidated her biological siblings for inheritance. am i wrong?