sold my AR to my buddy, he sent me this picture of broken carrier pin, says it needs the whole bolt carrier assembly because when it broke it scratched the inside

I could 1) give him his money back 2) buy the part for him 3) tell him to shove it

He's my buddy so I don't want to be a hard ass about it, the pin cost 9$ vs 100-150 for assembly.... could it have scratched it, never failed to shoot and he shot it last time it was shot so we didn't know about it. It was discovered when he was cleaning it , thanks for replies