11.5V = Dead Cell?

This is the same roundabout way I'm getting on with another guy here on the Forum who wants to shoot his alternator LOL he's killed the battery several times and now is blaming the alternator for not running correctly.. did he thoroughly charge his battery and verify it was a good battery before he hooked the alternator up to it or did he jump start it and then let the alternator charge its brains out until it was dead again ..
He's slow to post so I'm being patient..