i think if you speak to ranger andy and pass his speech check BEFORE you get raul as a companion, raul won't respond to your conversation, these quest triggers obsidian made for companions really svck.

I believe there are multiple people to speak to to get the appropriate responses.. From what I understand the companions have trigger words and time periods of waiting before those words will trigger a response. After so many triggers the quest will continue. I'm not positive about that as I haven't got to Raul's quest yet or read about it.