Riyad-us-Saliheen 907
Ibn 'Abbas (May Allah be pleased with them) reported: The Prophet (PBUH) visited a bedouin who was sick. Whenever he visited an ailing person, he would say, "La ba'sa, tahurun in sha' Allah [No harm, (it will be a) purification (from sins), if Allah wills]."
[Al-Bukhari]
According to this Hadith, a patient should be told that his disease will purge out his sins. To sit beside the sick, to comfort his heart and to say a few words of sympathy to him was the Prophet's practice.