Does Hajj fall away from the deceased who was not financially able to perform it, or is it obligatory upon his son, who has performed Hajj for himself, to perform Hajj on his behalf?

Hajj is one of the pillars of Islam, and scholars have agreed that its obligation is conditioned upon ability (istita'ah), based on Allah's saying: "And Hajj (pilgrimage to Makkah) to the House (Ka'bah) is a duty that mankind owes to Allah, those who can afford the expenses (for one's conveyance and provision, etc.)" (Surat Al 'Imran, 3:97). Ability refers to the financial capacity to cover the cost of provisions and transport beyond one's basic needs and the expenses of those one is obligated to support, along with physical capability and safety of the route.

If the father passed away and was not able to perform Hajj throughout his life, the obligation is lifted from him. As for performing Hajj on his behalf after his death, scholars have differed on this matter: Some consider it impermissible, citing Allah's saying: "And that man can have nothing but what he does" (Surat An-Najm, 53:39). Others consider it permissible by analogy with charity and seeking forgiveness. The preponderant view is that it is recommended to perform Hajj on his behalf as an act of piety, based on the Prophet's (peace be upon him) saying to Abu Razeen: "Perform Hajj and 'Umrah on behalf of your father."