the closest to a "happy ending" they could've gotten was her being taken away by CPS and reuniting in the future
Could've had his family volunteer to take her in when her parents get hauled off to prison. If she's in high school, odds are she's old enough to have a voice in what happens, and if someone says they'd be happy to have her added to their family, and she wants that too, there's a chance it'd happen.
I know someone who was raised by their childhood friend's family when their parents died with no next of kin willing to take them in. It was the foster care system or the friends across the street who said "we've always wanted another kid, and they get along well with our family, why not?". IIRC that happened when they were 14, so...