My mind has gone there, too, with the way they've been acting:
- The attorney was the one to report BL missing, not his parents.
- We have very sparse details available about his disappearance (what time he left, what clothes he was wearing, etc)
- They initially gave the wrong date for when he'd supposedly left their home.
- They removed the Mustang--presumably BL's means of transportation--from the preserve
- They had to be asked to join the search for their son.
- There were two 9-1-1 calls to their house on the 10th (Who placed the calls, and why? [speculation: could this be when they found out the truth, sparking a confrontation?])
- Their demeanor toward their daughter has changed markedly between the camping trip at Fort De Soto and now, when they won't even speak to her
- BL has still not been found, nor was there any sign of him having been camped out at the preserve
Obviously, there could be other possible explanations for these things, but the longer he remains missing, the less likely I think it is that he's alive.