I accidentally massacred everyone at Last Light Inn. (wrong choice in "welcome" dialogue with Jaheira) Then I had the chance to "talk to the dead" with Rolan. That was interesting. I recommend to do that, if he falls for some reason.
Asking his name , he says "Rolan", stressing that it is just Rolan, he has no family name.
Asking about his family, he says he has none.
You can then ask him about Cal and Lia. He says that they are brother and sister, but that he has no family.
So that was interesting, given Rolan's heavy atttachment to Cal and Lia and his feeling of responsibility towards them, it turns out they are not family in the blood.
This could have been worked out further in the story. I guess there was no time to do this.