I think you are grossly misjudging Jeb Bush's actions and his reasons for obeying the law.
What Greer is doing and all the courts have ignored is denying her the opportunity to have food or water by mouth. That is euthanasia and is not permitted under Florida law. Whether she could take water or not is immaterial and in any case we don't know what would happen, at least it would give her a chance and she has none right now. On this order at least the Shindler's have the law on their side -- giving water by mouth is not in any shape, fashion or form artificial life support as mentioned in the Florida statute. Any outcome of a trial of drinking, even death by choking, is preferable to what is going on now.
What I cannot figure out is why Jeb Bush and her parents are so focused on getting the feeding tube back in when it is clear that this will not happen when this other clearly illegal order by Greer is apparently going unchallenged.