Would my buddy have to pay back his bonus?

I got a soldier who is a good friend f mine who is getting chaptered and did get a bonus but only recieved a lil bit of it and our NCO told us that he would only have to pay back only the portion of it that he didn't recieve but another NCO a SSG said he wouldn't pay anything back because to get your bonus all you had to do was complete basic and AIT, also how would they make him pay it would they take it out in whole or how would it work and is my NCO correct on how what he would pay back and who is right theSSG or the other NCO?(it is a sign on bonus not a reenlistment and it is a honorable discharge if that helps).