Strongly suspect that parents know where BL is (they show no sign of being even remotely concerned about his well-being, no appeals, no interviews, just totally clamming up and visiting lawyer).
Lawyer will have told them in no uncertain terms that if they are protecting BL they are staring down the barrel of a Federal gun. They are not that young. Moreover, people are going to hate them if they've been assisting BL.
Cops are going to be very, very, very pissed at them if the whole search has been a wild goose chase or they've been withholding info.
It is clearly in BL's best interests to turn himself in at this point (as it always was).
At some point they're going to fold.
The weirdest thing to me is that they don't seem to feel that under pressure.