Young couple goes on van tour of US, boy comes back with van - no girl

The only question I’m really concerned with is how much/little did his parents know - I really don’t care how he died (unless his parents did it — like some Of Mice and Men sorta deal)
I'm curious how he actually accomplished something like that, but don't really care either in the big scheme. I think the parents are an oddity. They "cared" enough to lawyer him up but then seemingly do nothing to save his life like prevent him from going on the run. In my view, his death is the only conceivable outcome. Or did they really think he was an Eric Rudolph?