1. Please ask your mom to find someone on the same flight to assist in filling up forms.
2.Read the rules at Canada Board services to prepare luggage and report (B4 form) to avoid any possible problem. You can pre-fill up the form for her and ask her to present the print to the officer and sign at that time.
3. Telling the story of reality is no harm in these situations.
4. Request translator to assist if possible. If no possible, you wait at the airport. Your Mom tell them your name and phone number. You could be let in to be the translator.
Wish you enjoy the safe and joy life.