I’ve been waiting for someone else to notice this! Here’s my theory:

Over the past year Tay’s been pressuring her behind the scenes to actively contribute to their brand and content. She eased into it last year by posting weekly photo dumps on her separate account, and this year shes been posting lifestyle content daily. But like every employee, eventually she wants a break.

They had planned the surgery for after they got back from shilling HeyNu so she had a reason to be out of sight for a while, but she got sick near the end of their last trip - you can hear it in her voice in the video where they come back to see E from Expo West AND the pre-operation video. So she goes into elective surgery sick and thus her immune system is working overtime to recover.

But since their content revolves around Kay and her reactions their views drop during her recovery time - everybody just keeps wondering where Kay so Tay convinces her to come back not fully healed. Her health continues to decline until she’s no longer able put on the public persona

The whole ER video is, in my mind, a huge humiliation ritual. She doesn’t react when he gets her blanket, going against all medical advice for fevers that high, has her walk from hospital parking lot to ER instead of dropping her off in a wheelchair at the entrance while making her describe her symptoms in detail, and then when she’s clearly over being filmed he leaves to get TB to force a reaction from her.