Frosty is sick

Sarah's cat, Frosty is very sick. We got Frosty for her two Xmas's ago. Someone found him outside nearly frozen and took him to the vets. they revived him and we adopted him. He was only about 8 weeks old. She loves him so much. I know he is just a cat, but they become a part of your home. Over the weekend I noticed he was being really quiet. On Sun he did not eat or drink and he slept way more then normal. She thought he was being super cuddly. I took him to the vets Mon morning and his temp was way up, his blood count was dangerously low. The amount of red cells should be around 33 and his was 9. They did more blood work and redid his leukemia and other tests. They think he had some kind of autoimmune thing that is attacking his blood. They are treating him with an IV and steroids. I called this morning and his blood count came up a little so they said that was encouraging but he is still not out of the woods. It broke my heart to have to tell her, she was so upset. I laid in bed with her last night as she cried herself to sleep and me crying along with her. I know I will never allow another pet in this house, I can't handle how heartbroken my kids are when something happens. I am posting from work so I will post a picture of Sarah and Frosty from home.