Is it allowed to kill a disabled cat who is not able survive by itself; it is difficult to keep it at home as it needs to be taken care of like a baby its whole life.

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.

If this cat is capable of any kind of movement that makes it able to look for food, or if there is hope that someone might take care of it and be kind to it, then it is impermissible to kill it. However, if it cannot move and it is feared that it would suffer and perish, then some scholars held that it is allowed to kill it in order to spare it the suffering. The Maaliki scholars of Fiqh were among the scholars who held this view. Ad-Dardeer said in his commentary on Mukhtasar Khaleel, "An example is slaughtering the animal whose flesh is not lawful for consumption, such as a donkey or a mule; if it is sick and there is no hope for its recovery, then it is permissible, and even recommended, to slaughter it to end its suffering."

Ad-Dusooqi commented, saying, "i.e. there is no hope of benefiting from it because of a sickness or blindness or because of a situation such as the case when it is in a deserted place where no food is available for it and there is no hope that someone might take it and feed it."

For more benefit, please refer to fatwa 99417.

Allah knows best.