Hi, welcome to MobileRead!
You can use a Kindle in Canada and download content via the usb cable. There is some information in this thread about using a kindle outwith the US. (Feel free to post questions in the 'What device should I buy thread' as well.)
https://www.mobileread.com/forums/showthread.php?t=45876
My son, who has reading difficulties, uses my Sony 505, with a large font size and coloured overlays. Most of the devices mentioned will also allow her to put her own text documents onto it.
As kelly suggests, also think about what your daughter plans to read on it. Make a list of her top 10 books then search the different ebookstores. This will give you a good idea of where you will find the most content and which ebook format they are available in. This is a good ebook comparision site to check as well as the Sony and Kindle ebookstores.
http://www.ebookprice.info/