Steve,
For
temporary insurance, insurers do not accept licences from Australia, USA or Canada. Therefore you will not be able to insure your cousin on your car for 3 weeks. However you can ask your cousin to get an international cover from Canada itself so that he can drive your car when he gets here (the same thing that British people do when they go abroad, get for example a European Insurance Cover Note from their insurers before travelling). This will be a better option for both of you.
