My parents do not know any English words. Before they visited me last year,
1). I ordered China Airline tickets for them. The China Airline served chinese food which my parents would like to eat, and there were many chinese passengers whome they could talk to during their flying.
2). I sent them a step-by-step travelling instruction which they could follow (like a lab test procedure), including a long talk on phone.
3). I asked them always carrying language cards. I wrote Chinese and English questions on the cards, such as "I do not know English, and I need a chinese translater" if they met a officer, "Could you lead me to check-in desk, and I am going to Ottawa" when they were in Vancouver airport, "Could you call my son, his number is *****" if they were in an uncomfortable situations, ......
There was no problem, and they had fun during their travel. The only concern was that I worried too much as they said.
If you require special service for old people from Air Canada, they will arrange people in Vancouver airport to meet you, help in transfer and even allow you to take the electrial-driven cart to transfer bewteen termainls if you are not good in walking. Just ask them to get the detail. In Vancouver, they could even arrange someone know mandrian to help you. I heard that you can also ask for special food on airplane if you have special diet requrement due to health or habit.