How to show programs installed with brew in Launchpad?
If the installed package has a .app, you can add a symlink to it inside your ~/Applications folder.

Launchpad will pick it up from there. 

However, most packages installed by homebrew aren't what OS X calls "Applications", so you might not be able to do it out of the box. 

An alternative would be to create an Automator workflow that runs a shell script, and save that workflow as an app.