I'm trying to find out if I can apply for a green card as a Canadian Citizen through my mother who was a permanent resident in the US but passed away

It does not sound as if you have a road to the green card through your mother who was a permanent resident and passed away. There is no humanitarian reinstatement. You will have to find some other way to immigrate. I suggest that you visit with an immigration lawyer who can go over your situation and explain your immigration options.Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.