Brothers & Sisters' Walker family has overcome cancer and a miscarriage this season, and it has dealt with the loss of the family business. What else could go wrong?Sally Field ). Who would hold everyone together? "She is there to save her family, and I think in the finale, she is mostly invested in making sure the family stays together," executive producer David Marshall Grant tells TVGuide.com. With Nora through the episode is Sarah (Rachel Griffiths), as the two join Kitty (Calista Flockhart) on the campaign trail. Based on what Grant has planned for Sarah and Luc (Gilles Marini, who reportedly will be a series regular in Season 5), Sarah seems an unlikely candidate for a dirt nap.Matthew Rhys) and Scotty (Luke MacFarlane), who found out their surrogate is pregnant. Grant says while biology takes it course, Kevin and Scotty will help Uncle Saul (Ron Rifkin) explore opening a restaurant. But, Grant teases, "they go through a very intense story as well."Justin (Dave Annable) and Rebecca (Emily VanCamp), meanwhile, consider a trial separation to deal with their growing marital problems. "They are both starting to see very different futures for themselves," Grant says. "I don't think it's in any way a question of their love — the clearly love each other. They just have two different ideas of how they want to live their lives. I think that's often the case with young couples: You just have to figure out how you're going to do it together."Rob Lowe, whose announced departure from the show make him the most obvious candidate to die. And considering Robert's recent dealings with Bill Stanton (Patrick St. Esprit), who Robert was trying to catch in a political corruption scheme, there are plenty of ways for Robert to leave the show — alive or dead."This situation with Stanton could turn dangerous for him," Grant says. "He also certainly has his health to worry about, which has been an ongoing issue for him. And we have the relationship between Kitty and Robert, which has been up and down and could certainly hit a crisis if the situation with Stanton became a problem for Kitty's campaign. There are many options, and we had a lot of fun with that in the finale."Even so, Grant says there will be a possibility for Lowe's character to return in some capacity in the future.