Is it permissible to kill a friend who is addicted to heroin, has contracted AIDS and hepatitis, escapes from treatment centers, and for whom there is no hope of recovery?

Unjustly killing a forbidden soul is one of the gravest sins. The fact that the killer is a drug addict and suffers from AIDS and hepatitis virus does not permit this; rather, it calls for compassion towards him. He should be reminded of Allah, urged to repent, turn to Allah, and utilize what remains of his life in acts of obedience, for death is near, and the door of repentance is open no matter how great the sins, as Allah Almighty says: "Say, "O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful."" [Az-Zumar:53], and His saying: "Except for those who repent, believe, and do righteous work. For them Allah will replace their evil deeds with good. And ever is Allah Forgiving and Merciful." [Al-Furqan: 70].