He only need all project files from the publish folder.
But first run the published game yourself, to see if there all files in the publish folder.
If you run the game and there is no error like "file thisfile.bmp cant find" or something like that you can send it directly (or you make a archiv file from your folder (zip/rar)) to your friend.
If you run the game and there is a error like this from above, you should put the missing files into the folder.

A installer is only a programm, that puts the published/game folder into a other directory and make a connection to the game on your desktop.
So you dont need it for starting the game.

I hope you understand all what i write.
Sorry for my bad english.
Greetings Ralph.