Not an expert on PT citizenship law but was curious about the specifics.
Per Wikipedia -
https://en.wikipedia.org/wiki/Portugues ... nality_law:
"Children born overseas to a Portuguese parent are eligible to acquire citizenship by descent if their births are registered at a Portuguese diplomatic mission or
if they register as citizens at any later point. "
Your mother was Portuguese at the time of your birth - her passport being expired doesn't mean she lost citizenship, and dual citizenship is allowed.
Maybe an inquiry at a Portuguese consulate or the embassy will point you in the right direction, who knows it could be a straightforward application without expensive lawyer fees (hopefully).
This is what I found on the embassy's consular information (
https://otava.embaixadaportugal.mne.gov ... nformation):
Quote:
"I’m over 18 years old and I’m the child of a Portuguese citizen(s). How do I apply for Portuguese citizenship?
If you were born in Québec, we will need Copie d’Acte de Naissance issued by the Directeur de l’état civil du Québec;
If you were born in Ontario we will need the Certified Copy of Birth Registration issued by the Ontario Registry General.
Your valid passport;
Any Portuguese Identification document if both parents are Portuguese. Valid passport for the parent who is not Portuguese.
Birth Certificate of the foreign parent, names of their parents must be clearly shown on the birth certificate.
If at the time of birth of the child the parents were married, divorced, or widowed, this status must be updated in Portugal"
