“His disciples replied, ‘Lord, if he sleeps, he will get better.'” (11)
In verse 7 Jesus said to his disciples, “let US go back to Judea”. They respond, but the Jews wanted to kill you and YOU want to go back? Jesus then proceeds into metaphor where life is broken into hours in a day. They were perhaps (understandably) confused. He then tells them that Lazarus has fallen asleep and that he (Jesus) was going to go and wake him (Lazarus) up. Sleep is a common metaphor for death. But the disciples don’t take Jesus to be metaphorical. It may have been the “…I am going there to wake him up.” that threw them off. Dead people didn’t wake up.
If he sleeps, then he will get better. In other words, there’s really no reason to make the trip to Judea at this point. The disciples don’t seem to question Jesus’ ability to see what’s going on in Bethany. But at the same time, I read this text as though they really didn’t want to go back to Bethany as it most assuredly meant trouble.