It was as if he'd remembered how fragile your delicate human life was. He'd never forgotten that, of course, being around you - in your relationship, God forbid - he'd always thought of keeping you safe. Just today... it was as if a painful realisation had come. How tender you are. how... real you are and how easy it is to make you bleed. Underneath all your relentless, good-hearted heroics, he forgot that underneath the armour, you're just a human being.
His own death didn't scare him so much. Let it go, what would come? Oblivion? Some kind of peace? The dead don't care much, unless necromancers bother them after death. But your death... it frightens him. It makes him terrified. What will he do without you?
He won't even think about it. If you weren't in this world, he'd positively end this all without a second thought, find a stake to pierce his heart. he doesn't want to, he doesn't want to live in a world where nobody wants him.
You took quite a beating in the last fight. In fact, a lot. The spell that keeps you from being cured by Shadowheart magic had all companions worried... and that's why he's watching you sleep so carefully. He doesn't even know that you're awake. Outside his tent, the night is humming with the sounds of nature.
His head on your chest, he listens to your heartbeat and his anxious thoughts are calmed. You are here, breathing... As long as you are safe, his sense of life will not run out.