Just delurking with a few thoughts that popped into mind...
I am shocked at how much medical care costs in the US! :O I am extremely grateful that where I live it (Ontario, Canada) is free, or I don't know what we'd do!!! Not trying to rub it in at all- just shocked at reality outside my area! For all we know, maybe they wanted to make fake id/passports to come to Canada.
As for Z's dad- likely making minimum wage, but probably supplemented by SM selling drugs? Anyway, they probably moved so much partly because of all the bad rent & food checks, if what money they had was going for drugs.
About previous mention of a possible 'mercy' killing cover-up...I find it highly unlikely that 'mercy' is a quality known to the sadistic SM.
Another thing that is noticeable about Z's clothes- nothing girly at all that I've noticed. All seems to be totally SM's taste. Aside from the one pic of Z at the wedding in the pretty red dress- everything I've seen her in since has been dark and not like what most girls her age would wear, as if she had no control or choice whatsoever what she was allowed to wear. My own daughter her age and her friends all are very particular about what they want to wear, and mostly all at least some girly styles.