Is it all about paying attention?

I was going to run away from home this weekend, ooooo, just for the weekend, not forever.  That fell thru , so I have kept busy at home.  Funny, the things you notice if you pay attention.  I was up around 7:30 (I'm getting better!  Not 5:00 any more!) and did my usual routine with the breakfast and coffee stuff.  I was on my lappy by 8:30, just messing around, and around 9:00 hubby got up and came downstairs.  He made himself a cup of coffee and I started playing WoW.  I don't think he drank the coffee.  He looked outside, sat down in a chair, and proceeded to fall asleep, again.  In the chair.  Hmmmm.  Two hours later, I'm still playing WoW and he's still in the chair with his head on his chest.  I got up to make a cup of tea and this sorta woke him up.  He did move a little.  I settled back in for tea and WoW, and he was back to the head on the chest thing.  Just before noon I took a shower, then came down to grab some lunch.  Well, he's alive!  Staring at the great out of doors again.  His comment was, "the grass is still wet".  So, I ate lunch, and decided to be Suzy Homemaker for a little while.  I was upstairs cleaning stuff (yuk!) for maybe 45 mins, came down to get something, he's asleep on the couch.  WTF?  We are now talking prolly 12 out of 13 hours he's been sleeping.  He moved from the bed, to the chair, to the couch, but was only awake for minutes before he was out like a light again.  This is a bit unusual, altho he can sleep a lot if he is bored.  Wish I could do that!  But, it begs the question, why?  I know his cancer has recurred.  I also am very, very aware of his age.  But, this seems different.  Or, am I just paying attention?  We shall see.