A man asked the Prophet ﷺ, "Messenger of Allah, my father reached the time of Islam as a very old man who cannot remain steady on his mount. Shall I perform Hajj on his behalf?"The Prophet ﷺ replied, "Tell me, if your father had a debt and you paid it off for him, would that suffice?"The man said, "Yes."The Prophet ﷺ said, "Then perform Hajj on behalf of your father."
حدثنا هشيم حدثنا يحيى بن أبي إسحاق عن سليمان بن يسار عن عبد الله بن عباس أو
أن رجلا سأل النبي ﷺ فقال يا رسول الله إن أبي أدركه الإسلام وهو شيخ كبير لا يثبت على راحلته أفأحج عنه قال أرأيت لو كان عليه دين فقضيته عنه أكان يجزيه قال نعم قال فاحجج عن أبيك
Its isnad is sahih. Yahya bin Abu Ishaq Hadrami Nahwi is trustworthy, he was a memorizer of the Quran and knowledgeable in Arabic and grammar. In H and K it appears as Yahya bin Ishaq, which is an error, and the correctness of this is shown by the isnad that follows right after this one.Ubaydullah bin Abbas was a minor companion, and his musnad containing a single hadith will come at 1837. In Tahdhib, 20, it states that Ali bin Abdul-Aziz narrated in his Musnad, with a chain whose men are trustworthy, from Ubaydullah bin Abbas, that he used to ride behind the Prophet ﷺ, and then he mentioned the story.It appears that the hadith is actually the hadith of Fadl, narrated from him by his two brothers Abdullah and Ubaydullah, sometimes narrating it from him directly and sometimes narrating it without a full chain back to him. Sulayman is a senior successor, but he did not meet Fadl since Fadl died before his time, and it will come at 1818 that he narrates the hadith from Ibn Abbas, meaning Abdullah bin Abbas, from Fadl, and that is the correct version. In my view, the more likely conclusion is that the error in this narration comes from Yahya bin Abu Ishaq.