Yes, She is not orphan, She is daughter of my sister in law. But I have sufficient evidence, like school record documents, which I and my spouse signing from last 15 years as parents or guardians.
This is much more complicated than just adopting. There will likely have to be some investigation into whether the mother is actually unfit or could the father just provide a better quality of life. This is not straight forward even after adoption. I would seek Canadian legal council.