Does Hajj become waived for a person with an amputated left leg who is able to walk with the aid of a prosthetic leg, and has the financial capacity for Hajj?

If your father is able to perform Hajj by himself without extreme difficulty, then he must perform the Hajj al-Islam, even if he has one amputated leg and walks with a prosthetic one, as long as he finds someone to assist him and facilitate the performance of the rituals for him, just like a blind person or someone with amputated hands and legs if they find someone to assist them.

However, if he cannot perform Hajj except with extreme difficulty, and he does not find anyone to assist him, then he is considered like an incapacitated person (madhoob), and Hajj by himself is waived for him. But if he possesses wealth and finds someone to perform Hajj on his behalf (nā’ib), then deputizing someone for Hajj becomes obligatory upon him, provided that the deputy has already performed Hajj for himself.