It was only duty that made him get up in the morning. The duty of a promise he'd made. Duty to a dead man.
He regretted the promise, rued the fact it made him enter a house of mourning. As if his own grief needed to be darkened further; as if he needed the added pain of entering a house where dreams had been built, now so empty, echoing like a cavern and only inhabited by Rex.

It was his night to watch over Rex. Sometimes, he wished Peter would call him to say Rex had died; anything not to have to enter that lifeless cavern of a house where he could still see Richard in every room.
But the promise bound him and even his grief would not keep him from his duty. So, he would go and sit with Rex and try not to look anywhere but at the book he brought and would not read.
Later, with the lights out, he would lie awake listening to Rex being awake listening for Richard. Hoping Rex would catch the sound of Richard's car, as if it had all been a bad dream; but the car had been sold and Richard was dead and both Rex and he were dying, bleeding out their souls.
Sometimes, Christian hoped Höllerer would come by in the morning and find them both dead and Richard's car parked outside.