is not exactly known for its depth of characterization-- nor is George Lucas known for his depth or insight. The death of the aunt and uncle free Luke up to go off on a big adventure where things blow up; they are never mentioned or thought of again. Leia is both tortured and forced to watch her entire planet of billions of people
incinerated, and it has no long-term effect on her. In the prequels, her mother is actually turned on when Darth Skywalker commits genocide.
Thinking about the SW characters as if they were real people is just creepy. It's best to just sit back and watch the explosions.