I am looking for a home or a sanctuary for a cat I believe may have feline leukemia. This cat is outside and the owner has other cats and doesn't want it exposing the other cats. This cat is super friendly and does not deserve to be put out.

Take her. To humane society also call veternarian they have a cure for. That at that veternarian also go online and look up free veternarian care and health care for feline cats also some veternarian clinics & vet,hospitals will guide you in the right directions ask for phone numbers to call about getting free vasinactions shots for the sick cat because they have a cure for that also you could call aspa or call around your phone has google on it ask it to give you phone numbers for free vascanation shots and free vet care for a sick cat call the aspca and tell them your neighbor has been mistreating his cat and horibile living condition also tell then the cat is sick and needs vet care

That kitty should be tested for feline leukemia and if she doesn't have it, vaccinated for it