With a noticeable dilation to the eyes, his medications, and the observed disorientation, that does constitute an emergency visit for me.
There is no way for me to know if there are neurologic changes as a result of a change in the thyroid regulation or advancement of the kidney disease.
Either way, I would not want your cat to remain disoriented and/or nauseated through the evening. Much better to get supportive care and an evaluation ASAP, in my opinion.
I would have to say it completely depends on if it is a primary neurologic problem, which may not be so easy to address, if it is due to a systemic issue (like the thyroid or kidneys). It all depends on the exam and recheck of some tests. Only then, can we determine what supportive care may be of any benefit.