The Prophet (may Allah's peace and blessings be upon him) visited Sa‘d ibn Abi Waqqās, when he was sick and said three times: "O Allah, cure Sa‘d." This Hadīth indicates that it is from the Sunnah to visit a sick Muslim. It also indicates the Prophet's exemplary character, and his good manners with his companions, as he used to visit the sick and make supplication for them. This Hadīth serves as proof that it is desirable to make supplication saying: "O Allah, cure so and so," and one should name the person and repeat this supplication three times. This could be a reason for the person's recovery.
صحيح مسلم, ترقيم محمد فؤاد عبد الباقي, دار إحياء التراث العربي, بيروت. دليل الفالحين لطرق رياض الصالحين لمحمد بن علان الصديقي, دار الكتاب العربي. شرح رياض الصالحين لابن عثيمين , دار الوطن للنشر، الرياض, الطبعة: 1426 هـ. بهجة الناظرين شرح رياض الصالحين لسليم الهلالي, دار ابن الجوزي. نزهة المتقين شرح رياض الصالحين لمجموعة من الباحثين, مؤسسة الرسالة, الطبعة الرابعة عشر, 1407ه.