What was the explanation of our client seeming to connect to his departed loved ones through a psychic medium, yet we were told a number of them were not in the light?

This was a misinterpretation by the psychic as to the origin. They were connecting to the higher self and getting information about the individuals, but not reaching the extension of the soul that had passed. So this was a miscommunication and misinterpretation, and not a conflict in any way with your assessment. These beings were not yet in the light, that does not mean they cannot be communicated with in some way, either at a soul level, at the level of higher self, or as an earthbound spirit. In this instance, this was higher self sourced information coming through.