My 85 Year Old Father Has Dementia But Is Otherwise

My 85 year old father has dementia but is otherwise healthy and takes no other medication. My step mom just told me that he had an episode on Friday night where he was very cold, especially his feet, was somewhat disoriented and was unable to sleep. He did not have a fever, nausea, congestion or anything else out if the ordinary. She said he was still kind of "out of it" yesterday but seems better today. JD is no longer experiencing the coldness. I am curious as to what nay cause the temporary inability to get warm. They will schedule an appointment first thing in the morning. Thank you.