I have successfully Installed mactex using brew as shown below
$ brew cask install mactex
==> Satisfying dependencies
==> Downloading http://mirror.ctan.org/systems/mac/mactex/mactex-20170524.pkg
Already downloaded: /Users/amar/Library/Caches/Homebrew/Cask/mactex--20170524
.pkg
==> Verifying checksum for Cask mactex
==> Installing Cask mactex
==> Running installer for mactex; your password may be necessary.
==> Package installers may write to any location; options such as --appdir are
Password:
==> installer: Package name is MacTeX-2017
==> installer: Installing at base path /
==> installer: The install was successful.
mactex was successfully installed!
The issue is that how do I launch it now. I am not able to find it in applications or using search (command + space)

TeXShopand not MAcTeX. Then write your document and run it. – Nov 22 '17 at 09:08homebrewsimply downloads the MacTeX installer and runs it in this case, so you end up with a regular MacTeX installation. – Alan Munn Nov 22 '17 at 23:35