I'll limit my observations here to some non-lethal quibbles:
In real life the NCIS team would have given DiNozzo Senior special dispensations due to his work in past episodes helping NCIS, especially being crucial in solving the the murder case and preventing the sale of an errant nuclear bomb in "Broken Arrow." For example, they didn't have to hand cuff him. They never even made a reference to his past help in this current episode.
Here they handcuff Senior and take him to Interrogation, yet initially don't tell him why they are doing it, that a dead body was found in the trunk of his car. That seems harsh (see above paragraph) and even illegal.
Interesting to note that this is one of so MANY cases that NCIS solved because the bad guys took the extra effort to frame someone for the crime, while if they just simply murdered the guy and left it at that, they would likely get away with it. In this episode the murderer really didn't need to frame someone; anyone could have been the murderer since the victim mistreated everyone who crossed his path in business!
It was ill-manered and very inadvisable --at the end of the episode-- for Gibbs to discuss with Senior Senior's personal relationship with Tony while Gibbs knew that Tony was eavesdropping on the conversation. It's like letting someone listen in on a sensitive personal telephone conversation.