No, the exception to reading the Miranda rights means that anything he said could still be used as evidence again him. Which is the very opposite of what alot of people think the Miranda rights exception is for. It is not there to stop prosecutors from using collected evidence. It's there to allow them to continue to collect evidence while also questioning without the presence of an attorney and without the suspect being informed that he can remain silent. If he chose to remain silent then there wouldn't be anything anyone could do to force anything out of him. But if he does choose to talk then everything he says can be used in evidence.