If FBI: International wasn't coming to an end, I'd have more time for Wes Mitchell's backstory. However, there are only three episodes left, and I need to see Vo take over the Fly Team as the leader. The series has just offered a way to make that possible.
Caution: This post contains SPOILERS for FBI: International season 4, episode 19
In the most recent episode, Wes finally came face to face with his dad, Dean, whomade it very clear he hadn't changed. This was a man not sorry for the way he raised his son, and Wes wasn't going to sit there and listen to a fauxpology.
Then as Wes was about to leave, Dean dropped a bombshell. Wes has a sister. She's a freshman in high school, and it suddenly opens a door for Wes to move back to the United States.
Wes may want to see his sister grow up in FBI: International
One thing we've learned about Wes is that he is close to those he calls family. He talks to the man who raised him consistently, making it clear that he views that man as his dad and not Dean. With this in mind, there's no doubt that Wes will now want to consider moving back to the United States.
His sister is only around 14 or 15 if she's a freshman in high school. She'll need a big brother to look out for her, especially one in law enforcement. At the same time, it will allow him to protect her from Dean, who is sure to treat her the same way he treated Wes growing up as he's proven he's not sorry for his actions.
This opens a leadership position with the Fly Team
if Wes decides to leave in the FBI: International series finale, it opens the Fly Team leadership position again. This time, Vo would be able to take it.
A previous episode shared that there is a GS-14 position open in the States, and that Vo and Raines are both looked at for it. With Wes moving, it could allow one of them to get the Stateside GS-14 position and then the other take over the Fly Team leadership. I'm on board for either, but I think there's been more development for Vo to show that she is more capable of running the Fly Team.
Either way, FBI: International is setting the seeds for a change in leadership again, and having Vo (or Raines) take over the Fly Team would be a beautiful end to the series.