When I read your question, my first impulse was to stand up like an asshole at a horror movie and scream "DON'T GO IN THERE, YOU IDIOT! HE'S RIGHT IN THERE!
I'd say ninety-nine percent of the time, if someone's coming off of a messy breakup, the most you're going to get out of a relationship with them is some comfort sex, and that'll usually be followed by weeping jags, clingy midnight phone calls and possibly even crappy poetry.
If you just wanna tap that weepy ass, or get off on playing therapist, feel free. But know you're taking advantage of someone at their lowest point. If you think you could have a real relationship with this guy, give him some space, let him blast some Linkin Park in his room for a while, and check in again when he's no longer questioning all that life entails.
That time will allow him to get some perspective on the previous relationship, process all that pain into lessons he will hopefully apply to YOUR relationship, and, most importantly, give you time to figure out if that breakup is really going to stick. Nothing sucks more than nursing a wounded boyfriend back to health only to see him fly on back to his usual nest.
And yes, we do that. A lot. So keep your distance, be a friend, and wait for the right time to strike. It should be just when he's fully on the mend, but not yet put together enough to say anything but "yes" to the chance of dating you.