Is it permissible for a pilgrim in a state of ihram, who has had his left foot amputated and has a wound on his right foot, to wear khuffs (leather socks) during ihram, and does this entail an obligation to offer a sacrifice (hady), and what are the rituals for which proxy performance (inabah) is allowed?

There is no obligation on the one who wears a khuff on an amputated leg, due to the absence of a foot. It is permissible to wear it on the other leg if one is unable to wear a sandal due to an injury, because he is incapacitated from wearing a sandal. He must cut the khuff so that it is below the ankles. If he wears it without cutting it, then he must offer a fidyah (definition) according to the majority of scholars.