Jeez the accident she was involved in sure left her with extensive head injuries, and according to Doe Network she was a "known drug abuser"? Whether that means the occasional pot joint or mainlining hard drugs isn't clear but people acting irrationally following a head trauma is not uncommon, and drugs/booze would not make it any better. From the description of her condition it's quite obvious she was still in need of medical attention.
I guess Cazalas could be telling the truth about her just vanishing and she could still be alive on skid row somewhere or in a state hospital with amnesia or severe mental impairment due to her head trauma. That doesn't make it okay for Cazalas to just take her truck but his doing that doesn't necessarily mean he harmed her either. I think there is still hope for her family.
BTW what's a Marago camper? Never heard of that before.