Can an indoor cat become an outdoor cat?

my friend recently threw her cat out of the house (she has a bladder problem and literally pees everywhere, shes spend thousands and thousands of dollars on the cat and cant take it anymore) the reason she didnt want to give it to animal control or a shelter is because they would definitely kill a cat like that...no one would want him. she has food, water, and a cage (with bed) on the deck for the cat but besides that the cat cant come in...he seems VERY scared living outside and i told my friend to take him back in but she refuses, what should she do and will the cat get used to living outdoors?