Libel/slander/lawsuit ?s for story

In one of my stories, a popular family therapist/author/motivational speaker takes a major hit when his estranged son (who works in the same field) writes a book and goes on a talk show saying really bad and false things about his father. This hurts his credibility and causes him to lose money through cancelled seminars and reduced book sales.

My question is this:

If the speaker/author/etc doesn't want to sue his own son, would his publisher or publicist have grounds to sue? I think they would stand to lose a lot of money too. Would they be able to sue independently of the father?

Another side question, just a shot in the dark:
If it comes out that the father's ex wife planted a lot of lies in the son's head that come out in the book, could she be sued in any way? The son wrote what he did because he thought it was true, but it wasn't and can be proven (sort of). Also, her tendency to lie can be exhibited in other ways.

Thanks! A lot of this is based on a true story about my father and my brothers, but without the book deals or talk show appearances.

Necco-The mom told the son the lies about his father when he was growing up so there wouldn't be any reason for her to foresee that he would put everything into a book. The facts as to what happened in the divorce, etc might be able to be drawn up (example: she cashed the child support checks that she claimed not to have gotten), but other than that it's all 'he-said, she-said'. I thought of having her behavior be explained by some sort of disorder (maybe early onset Alzheimer's or schizophrenia or something) in addition to her just being a belligerent old hag, but that's not really going to be in the forefront.

Ben: I don't blame you! I wouldn't wish that train wreck on anyone.

Of course I would play up the details to the real story to be more interesting, but I don't really have to go very far.

The story line is more about a father and son reuniting after a very long estrangement...It's set up as a pilot to a drama but could be extended to a movie, I'm not sure. The lawsuit(s) would mainly serve as a way to force the father and son to talk to each other (if only through their lawyers) and attempt to sort out what actually happened and what lies were told to whom. I thought of having the son served with papers at his house (so I could have a conversation between him and his wife and him and his own son)...either that or a 'cease-and-desist' letter...but I wasn't sure if the publicist would be able to sue for damages if the father didn't want to go along with it.

The father (the MC) is very cold and distant, but the subject of his past and his kids (both estranged and 'local') is a major 'chink in his armor'. The relationships between him and his son and him and his current family are the focus.

Even if it weren't technically allowed in real life, would the idea of a publicist suing the son for damages (lost profits) be too 'out of the park'? Meaning, too unbelievable?

As for the 'slander by proxy', I wondered if that (meaning, exploring the option and the father and son reuniting) might be a setup for a more light-hearted type of series a la Ally McBeal or Lifetime's Drop Dead Diva?

And Necco...is that a bear in your avatar? Or a cat?