For parents and grandparents, the maximum stay is 2 years; they usually will be given a multiple entry as long as the validity of your passport or a period up to 10 years.

The Canadian inviter must meet the Canadian minimum income threshold. Based on the 2017 income requirement, the minimum necessary income for a family of 5, including the sponsor, is $51,846 CAD.

(http://www.cic.gc.ca/english/information/applications/guides/5256ETOC.asp#incometables)