Strange thing happen on way to accupuncture today

OK, I'm really stumped on this one. My husband who has stage 3, possibly 4 lung cancer, had his chemo on Monday, on Tuesday morning we both got up at regular time. Jerry wanted pancakes with fresh strawberries which he had bought at the store the day before. He mixed up the batter from scratch and I cooked the pancakes. He is diabetic so splenda was used instead of sugar and the maple syrup is also sugar free. After we ate I took the dog for a walk and my husband was lying on the couch looking at the food sales in the newspaper. As I went out the door he said he was going upstairs to cleanup for his accupuncture which was for 9 a.m. I walked the dog for about 20 mins and returned at about 25 mins till 9. The dog saw something in the back yard and ran to the door barking so I let her out and when I turned around I saw my husband still laying on the couch with the paper in his hands. He looked asleep so I called him and said he needed to get up. No response. I went to him and shook his arm and repeated he needed to get up. Still no response although he barely opened his eyes. I repeated this about 5 times then said I was calling 911 and did. They got here within mins. (which of course felt like hours) and took him to ER. At home they could get him to barely respond with his name and where he was and what day and year it was.
At the hospital they did all the monitoring and did a CT scan thinking he had a stroke.
5 hours later he was fine although he couldn't remember a thing about what had happened that morning. He had no problem with moving and lifting his head, arms, and legs and even moved himself from the gurney to the bed which they said they would observe him in for 24 hours.
A speech therapist was sent in and checked his speech, movements and even gave him water to drink and crackers to eat and found nothing wrong with him. The hospital doctor said he found nothing wrong with him but would have a neurologist check on him that evening.
By 8 p.m. I went home and this morning will go back and see if the neuro found anything wrong. But at this time we are totally stumped as to what happened to him.
Also three weeks ago his blood sugar level was at 400 and he was put back on metformin for his diabetes control and when they checked his blood sugar at the hospital it was 196, still high but had come way down from the previous weeks.
Anyone have any idea on what could have brought this on? I really don't want to go through something like this in the future it's hard enough with the chemo and rads.
Thanks,
Nancy