weird as he unhooked everything and rehooked everything with the battery unplugged. from looking at the picture, there was a positive and negative cable (red/ and black) that were screwed in. Could he have rehooked them backwards?
if he reversed the wires only thing that would have happened is the ammeter would read backwards ( show charge when it is discharging etc.)
you can even connect the ammeter wires together and the only thing that woule happen is the ammeter would not read at all. ( ammeters are in series with the flow of electricity)