Regarding the brain damage question daemons are often relatively resilient to it in an immediate sense - their brains are not damaged in the same injury, they can retain some faculties that their human has lost. But emotional states are still contagious. If the human is frustrated or psychotic or anxious or something, so is their daemon; contagion is theoretically two-way but if something's leaning on the switch in one brain the other can't fight back effectively.
Re: Questions for Relatively Major Greens
Regarding the brain damage question daemons are often relatively resilient to it in an immediate sense - their brains are not damaged in the same injury, they can retain some faculties that their human has lost. But emotional states are still contagious. If the human is frustrated or psychotic or anxious or something, so is their daemon; contagion is theoretically two-way but if something's leaning on the switch in one brain the other can't fight back effectively.