Sorry that I'm not able to provide many suggestions, as I'm not overly familiar with Toronto (although I have done a bit of research for a future trip). Would your relatives feel more at home staying near the "Little Italy" area or does that matter? Some of the Italians have moved out towards Vaughn, but AFAIK the Toronto neighborhood is still a vibrant area with lots of good restaurants.
Have a look at this website for more information.....
Toronto is an expensive city so staying in the "chain" hotels such as Best Western, Ramada, Comfort Inn or whatever will be more reasonably priced than the posh places like the Royal York. I'm sure Trip Advisor will have all the details.
I'm sure you've looked at this, but here are the options for getting into town from Pearson Airport.