The Prophet ﷺ said to a man, "You are the eldest of your father's children, so perform Hajj on his behalf."
حدثنا عبد الرحمن عن سفيان عن منصور عن مجاهد عن يوسف
أن النبي ﷺ قال لرجل أنت أكبر ولد أبيك فاحجج عنه
Its isnad is sahih. Yusuf bin Zubayr Makki, the freedman of Ibn Zubayr, is trustworthy and accepted. Nasai narrated the hadith in 5/120, number 2644, in the chapter on rites, on what is recommended for someone performing Hajj on another's behalf, and Bayhaqi in 4/329.