A great aunt died of alcoholic dementia at 999 Queen Street,Toronto. How could I find the address of her husband when she died and where she was buried in the hope of finding what became of him.

Records from the Queen Street Mental Health Centre are held at the Archives of Ontario. Depending upon the year your great aunt died, you may be able to access those records (more info). As for her husband, unless you know the city/town where he/they lived there isn't much you can do if they were living past the 1901 census (if living prior to the 1901 census check census records). If you know the city check their local directories or telephone books.