Europe - YUL-GVA-BEY with expired Lebanese passport

My cousin will be transiting through GVA on his way to BEY. He only has an expired Lebanese passport. Is there passport control in GVA if he is only transiting through on his way to his BEY flight?

Will he be able to get through with only an expired Lebanese passport?

Even if there's no passport control at GVA, how will he manage at YUL or BEY??!!

I don't think there's any exit passport control in Canada.

I don't suppose that the passenger will need to clear passport control in Geneva.

However, is the OP absolutely certain that a Lebanese citizen can enter Lebanon with an expired Lebanese passport. Even if that is so (and it might be), the passenger will still need to clear check-in at Montreal, and at Geneva the airline will no doubt to a check of passports for passengers boarding the flight. So unless the airline is happy with carrying a passenger with an expired passport, the passenger won't be able to board the flight in the first place.

In BEY he should be OK because he is Lebanese going back to Lebanon. I don't think they would refuse him entry to the country he was born in.

But YUL would be an issue as well. If YUL does allow him to go through, I'm wondering if he will have a problem in GVA?

Also, if the OP doesn't have his BP to BEY in YUL, he'll have to get landside at GVA hence pass Passport control

Simple answer is NO.

Just because there are no formal exit controls from Canada does not mean that one can simply exit the country by air without a valid passport (or equivalent document). The passenger will be denied at check-in.