He had been anticipating this for a while. The end was inevitable. It was as obvious as the sun was bright. He'd always been ready for it, had always known, deep down, it would come.
Everything was taken care of. He'd stopped off to see all of his companions, though of course they had no idea. He did it discreetly, after all, none of them recognised him, but all of them had been kind to the old man they passed in the street. The Tardis had been parked somewhere remote, but nearby. The keys lay on the ground next to it, and The Doctor could only hope it might fall into better hands.
He pondered for a minute at the word 'companion'. He looked at the bed beside his, and marvelled at how fitting it was. Rose Tyler, his best companion, was by his side again. She was dying, too. There was nothing in the entire universe that could have saved her, except maybe The Doctor. But his willpower had weakened considerably in his old age, and there was little hope left for either of them.
He leaned up, slowly making his way off the bed. It was an arduous process, one that took far too long and too much energy for his frail body. He had one and a half thousand years behind him, and it had finally begun to show.
He settled down on creaking joints in the chair besides her bed. He sank with a great wheeze, disturbing the coarse fabric of his hospital gown. He felt the last of his resolve slowly draining out of him, watching over Rose. He suspected she was also nearing the end, and he smiled weakly at the thought that maybe neither of them would have to die before the other.
Her eyes were open, but they were almost blank, as if there were something great and powerful and almighty that only she could see. The end of her life had been cold and unforgiving towards her, and it was now leaving her, once and for all.
He stood up on shaking legs to plant a kiss on her forehead softly. "Rose Tyler, I love you." He finished, collapsing back into his chair. His eyes were closing and he was barely awake. Rose held out a hand to stroke the back of his. "Rest." Was all she said.
And with that, The Doctor, one and a half thousand years old, the saver of planets and the destroyer of worlds, the last of the Time Lords, settled down in his chair, took a great sigh, and died.