This isn't the first time Mitchell has admitted this strange habit of sleeping with his eyes open. He regularly tells me that he will lay down for bed and even sleep if he has to, but he is not going to close his eyes! He makes that very clear.
Ben also claims an unusual sleeping habit: he doesn't sleep! Quite often, he tells me that he was awake all night long. When I ask him if he is tired then because of that he says, "No, I laid there quietly and rested, but didn't sleep." Sometimes he claims to have looked out the window all night, sometimes he read throughout the night. Sometimes he just played with his toys in bed until morning and was waiting for me, awake, when I came in to get him up for school.
Both boys make their claims with a straight face, no tell-tale giggling, and an honest look about them. I think they really believe it when they say it. No biggie to me. I don't really care how they sleep as long as they actually do sleep.
So one boy doesn't sleep at all, the other one sleeps, but keeps an eye or two open, so as not to miss what his sleepless brother is doing, I assume.