brew rmdeps
or
brew rmtree
See: Uninstall / remove a Homebrew package including all its dependencies
It is possible that if the user updated the application manually and not using brew that it will have to be uninstalled manually.
You can check and see if there are any receipts in your Receipts folder:
ls /private/var/db/receipts
and use the application's receipt .bom file and lsbom to Trash all files installed by the application as described here: Uninstall applications installed from packages Install
Homebrew seems to be taking the world by storm, according to Homebrew enthusiasts. I find Homebrew to be more or less incomplete, with barely any support, and has ambitions beyond its capability, perhaps because it is still in its infancy, or perhaps because it attempts to compete with a fully mature, complete, fully supported, end to end source and binary package management solution for OS X, i.e. MacPorts
homebrew-caskproject. – bdesham Apr 25 '14 at 16:06