No, he couldn't be alive. He was stabbed through the heart. He didn't have a code, if he did have a code he would not have been able to cast a geass on Schnizel at the end. As was learned from when they showed CC's past, when she gained her curse mark she lost her geass powers. Same thing happened to the Emperor. Note he did not cast another geass on Lelouch OR on Suzaku after attaining VV's curse mark.
CC was merely talking into the sky....you know like people tend to do when they "talk" to the dead.