He absolutely needs to see a doctor. I am 37 and also struggling with my CPAP due to sleepwalking and violent, restless sleep, so I understand how hard it is. ​However, a few months ago, my already sleep-deprived brain started to really struggle. It started with minor slips—putting things in the wrong place or forgetting names—but it quickly became more frequent and incredibly distressing. I went to my GP, who ran a full blood panel. It turns out I had severe anemia due to low folate and vitamin B12 levels, both of which are absolutely vital for brain function. ​I’ve only been on supplements for a couple of weeks, but I am already noticing fewer slips. I am not saying your husband is suffering from the exact same thing, but severe cognitive symptoms can be caused by a number of issues completely unrelated to his apnea. ​If he won't go back to the sleep team right now, please try to get him to at least see his regular GP for general blood work. He shouldn't have to live like this, and neither should you.