After what though? The whole play resolves? So could he have challenged after the run scored and negated the whole play? He was busy throwing and then covering home so that's a small window in between those 2 to do it, while extremely distracted.
That's the thing that confuses me about ABS. When do you challenge that when runners are going? You can't wait to challenge but I feel like you should be able to after the play on the field or something