This is not a spoiler, merely speculation based on the fact that outside of her husband, Johnny and Olivia who has had her own mental issues of late, only a close relative can have her committed and that leaves Trey. While Alexis pointed this out, she turned and glanced at Trey who has admitted to being Kate/Connie's son.
What I'm guessing is that Sonny and Alexis turn to Trey as their only hope to wrest Kate from Connie's clutches. It's ironic as both had wanted him out of Kristina's life, and Sonny would have cheerfully killed him. Now both find themselves needing his help, assuming that this is the way the tale unfolds, to force Kate/Connie into Shadybrook for treatment.
I'd love to see Trey and Kate finally able to make peace, for some healing to come out of the tragedy that has been playing out.