Im curious. I know he give you a location of his treasure, but so what... Besides i believe i have already found that treasure. Im more concerned with the consequences of his release. Is it a good thing? Or bad? Any imput would be helpful. Thanks.

No you haven't. It doesn't appear unless you've released him.

And no, according to the wiki, there are no consequences to releasing him.

if you are unsure the release him, get the treasure location and then kill him...problem solved.

From experience it was more beneficial to me to release him and offered no (seemingly) negative effects.