How is Justin's "family" different from Via's?

From the text:

i like olivia's family. they laugh a lot. my family's not like this at all. my mom and dad got divorced when i was four and they pretty much hate each other. i grew up spending half of every week in my dad's apartment in chelsea and the other half in my mom's place in brooklyn heights. i have a half brother who's five years older than me and barely knows i exist. for as long as i can remember, i've felt like my parents could hardly wait for me to be old enough to take care of myself.