The Messenger of Allah ﷺ said, "The completeness of visiting the sick is that one of you place his hand on the sick person's forehead," or he said, "on his hand, and ask him how he is. And the completeness of your greetings to one another is the handshake."
حدثنا سويد بن نصر أخبرنا عبد الله أخبرنا يحيى بن أيوب عن عبيد الله بن زحر عن علي بن يزيد عن القاسم أبي عبد الرحمن
أن رسول الله ﷺ قال تمام عيادة المريض أن يضع أحدكم يده على جبهته أو قال على يده فيسأله كيف هو وتمام تحياتكم بينكم المصافحة
[Its chain is daif] Ahmad narrated it: 5/260, from the hadith of Abdullah bin Mubarak, with the same wording. Ubaydullah bin Zahr and Ali bin Yazid are both daif, as previously mentioned.