The decision to go forward with the move of Tokitae back to her home waters was made with the guidance of dozens of industry professionals - scientists, vets, trainers, ect - who are hands-on working with her. It is those qualified professionals who have decided this move is in her best interest and, no offense, but I'm sure they know her limits better than people online with no relevant qualifications who have never met Toki.
Besides, the timeline is her moving in 18-24 months. Tokitae is setting longevity records every breath she takes, and she's sitting stagnant and alone in a rotting stadium with no protection from the elements. There's every chance she won't make it that long, and she'll die in that tank.
But we owe it to her - and to the Lummi Nation, and to every captive cetacean in much worse conditions - to at least try.