He heard the Prophet ﷺ say, "The sick person's sins fall away just as the leaves fall from a tree."
قال عبد الله حدثنا عقبة بن مكرم العمي قال حدثنا سلم بن قتيبة عن يونس بن أبي إسحاق عن إسماعيل بن أوسط عن خالد بن عبد الله
سمع النبي ﷺ يقول المريض تحات خطاياه كما يتحات ورق الشجر
Its isnad is hasan, because of what is in the one before it.As for Uqba bin Mukram Ammi, he is trustworthy, his hadith appears in Muslim, and he is the teacher of Abdullah bin Ahmad. This hadith is among his additions.Salm bin Qutayba is deemed trustworthy, and his hadith appears in Muslim.Ismail bin Awsat Bajali was the governor of Kufa. Ibn Hibban deemed him trustworthy, while Saji deemed him daif.See 11131. It is also found in Bukhari, 10/110, number 5647, Fath al-Bari.