www.widowed.ca contains information and detailed instructions to help someone file a tax return for a spouse or other loved one who has passed away. It is practical and useful information that any executor or widowed spouse will find essential. Click here to read it.
However, in my experience, an awful lot of widowed folks find it extremely difficult, if not impossible, to carry out detailed paperwork shortly after the death of their spouse. It's not that they aren't smart enough or capable enough; it's more that they are overwhelmed with the adjustments they must make to being on their own. Sometimes paperwork such as a tax return can be the last straw for someone who is struggling.
If you are struggling, call an accountant to complete the return. Don't feel that you must do everything yourself. There is nothing wrong with asking for help, particularly with complex paperwork such as tax returns and probate applications. An accountant will be able to provide you with all the advice and information you'll need.