The Texas-raised attorney is representing Nick, who is accused of murdering Rob, his father and the film's director

The family instructor tried to make the best of his behavioral issues by channeling them into 'A Chair in the Air.'

Nick Reiner was acting out of place at Conan O'Brien's Christmas party hours before his parents, Rob and Michele Reiner, were found stabbed to death in the couple's home ... and now there's a report of a strange interaction that concerned partygoers.

According to estate and trusts attorney Sean Weissbart, a partner at Blank Rome LLP who is not connected to the case, Nick will become ineligible to inherit from his parents' estate if he is ultimately convicted of the crime, per a particular state law.

Rob Reiner and Nick Reiner made an addiction movie, "Being Charlie," and premiered it at TIFF 2015. Interviews reveal a family's tragic struggles.

Reiner made four appearances on David Manheim's podcast 'Dopey,' but the host says that Reiner cut off communication after he asked for help in landing father Rob Reiner as a guest: "It pushed him away.