Restoring LGU+ Galaxy S2 to official factory firmware

Question

OK, this is going to be a lot to take. So, please don't get angry.

I'm in the US and my brother is in South Korea. He was recently given (for free) a working Samsung Galaxy S2 from the LGU+ network. After getting the phone and having it activated, he wanted to get rid of the Samsung and LGU+ add-on apps. So, he rooted it and deleted some things.

Now, all of the official Google apps are gone, and he says it's "acting wonky." I know that's not a very good description, but he's not terribly tech savvy. Normally I would assist him in these things but, as I said, he's in South Korea and I'm in the US.

Now, what he wants to do is to restore the phone to original firmware (or, if possible, an unaltered, unhacked, plain version of Android) and he's not sure how to proceed. He's using OSX Lion on a MacBook Air and, as far as I can tell, is using something called Heimdall. He does not have the capability of using Windows and he doesn't have the ability to use a Virtual Machine to install Windows on his laptop.

So, I know that this post is breaking a lot of rules but I've literally got nowhere else to turn.

Edit 1:

Here's the description he gave me:

I used a program called breakdroid which is a terminal application and it rooted the phone. Then, I used a free program called nobloat that can delete the apps. But when I looked at the applications list, all the names looked random like 11hfhhf3.fjjhh3aaaaa.ffhh3aaa. So, I deleted things with "Samsung," "LGU+," or "Google" in the filename. Now, I can't set a wallpaper and all of the Google apps are gone and I can't get them back.