She has to adopt him,as he is not orphaned he still has a father so tell your mother to look on the Canada Immigration web page on the left side under adopt.
This will tell you who can be sponsored under the family class
Who can be sponsored
You can sponsor:
•parents
•grandparents
•brothers or sisters, nephews or nieces, granddaughters or grandsons who are orphaned, under 18 years of age and not married or in a common-law relationship
•another relative of any age or relationship but only under specific conditions (see Note below)
•accompanying relatives of the above (for example, spouse, partner and dependent children).
So you see they have to be orphaned or adopted. and under 18
