I don't really know why Rikku cried so deeply when she noticed that he died. It first took it to mean that the Al Bhed as a whole seemed to have strong ties to eachother, as they were a persecuted people. It happens with many persons when under pressure - they band together and form feelings and ties akin to that of brother/sister. I always took it to be that.

Although, with the mention of his name, and why the game decided to focus suddenly on a character who had never heard or seen of before and then later there was no mention of him and his death... I don't know why, to be honest. One of many things Square enjoys doing in its plot and scenes - make us wonder, when there most likely is no real reason for it...