If your fuel tank exploded, you might have been coming down to the surface too hard. Next time try slowing down to under ten m/s at least when landing on the Mun. But if you want to rescue Jeb then send another mission to save him. You can send a probe one in case you make another mistake, or a manned mission if you want to get more science (Unless you are in sandbox) from the mission or just have the satisfaction if a successful Mun mission. It all depends on how lazy you are. Your other options are to just pretend it's a base and leave him there or post it on the KSP Reddit and hope for a Blunderbirds from Matt.
Duck McFuddle's post in the moon problem was marked as the answer