Leaving the island requires going through numerous checks, primarily to ensure that those departing cannot leak the island's secrets. Regardless of whether one is part of senior management or not, these procedures must be followed.
When Nina found out that Jazmine was leaving, she felt happy deep down. However, she was still worried and asked her mother some questions, "Mom, are you really planning to leave Dad behind and go?"
"It's not like I'm abandoning him. I've already told King that if he wants to leave, I'll take him back to the Tapia's house. My main priority is to take your Granddad home." Jazmine knew she had wasted quite a bit of everyone's time.
Charles was the one she took in, and now that his condition has stabilized, it's only natural to send him back.
As for Jonathan, his body was the subject of research. Doc Strange still had some final things to deal with, so he couldn't leave. As for Yoselin, it had nothing to do with her.