Robert Jordan meets Rafael outside of the cave when he arrives the first day. Rafael gives some information about the other members of the band, specifically Pilar and Maria.
Later that night, Rafael tells Robert Jordan that he should have killed Pablo, and tries to get him to do it again (not having the balls to do it himself). Robert Jordan refuses.
The next day, Rafael is sent to escort Anselmo to a spot where he can watch fascist traffic on the road. He then goes to the bridge to observe the sentries.
Rafael returns some time later that night to the cave, long after the snowstorm has begun. He doesn't want to go back for Anselmo, because he's hungry (and useless). So he tells Fernando how to find and Anselmo so he can bring him back.
After the confrontation with Pablo later that night, Rafael is in favor of killing Pablo. But we already knew that.
The next morning, a fascist patrolman gets through to the cave because someone was not at his sentry post. Rafael!
Instead, Rafael was off following a pair of fornicating bunnies. Hey, they were fat and juicy looking.
Rafael returns to the sentry spot with the hares sometime later, when Robert Jordan and the others are manning the machine gun there. He's dispatched to get them lunch.
The next morning, Rafael fights with Pilar's group in the assault on the upper sentry post.
Afterwards, he picks targets off on the other end of the busted bridge – he's a surprisingly good shot.
Rafael rides just before Robert Jordan in the escape attempt. Regrettably he's the one who makes it to safety.