When the dragon sleeps, his mind tries to find rest from his difficult life. Trying to remember what it felt like to be warm, wanted, found. His mind tries to give him the rest that his life cannot give — to let his guard down, at least for a moment.
This is his dream, his mind trying to find rest from a world that is cold toward him.
You should not be here. This is his dream.
The least you could do is have some respect and watch without disturbing him. Let him rest, at least for a moment.
Let the dragon rest in peace.