No. For parent sponsorship dependents can only be their children/grandchildren and must under 19 years or over 19 years with a disability. See below:
Dependent children
Refers to the children of the applicant and those of the spouse or common-law partner, if applicable.
They must be:
under the age of 19 and not have a spouse or common-law partner, or
19 years of age or older and unable to be financially self-sufficient since before the age of 19 due to a physical or mental condition.
Dependent child of a dependent child
Refers to children of dependent children of the applicant and those of the spouse or common-law partner, if applicable.