I am so very sorry about Butterscotch. My RB kitty Theo had an auto immune disease and severe anaemia with numbers low like yours. He was 13 years old and wasn't given much hope. We knew when a bout was coming on because he would lose his appetite, collapse and pant. Several times we rushed him into emergancy and with steroids and antibiotics he pulled up his numbers.
We thought several times that we would lose him and were ready to let him go peacefully but he rallied for us and went a little while longer. We couldn't bear to say good-bye. We were feeding him him with a stomach tube and he managed to hang on for us for about a year.
In the end the vet would not intervene anymore and we had to say goodbye. I don't know if I did the right thing by continuing to intervene...but I feel neither Theo or I were ready to say goodbye.
Butterscotch may rally and surprise you and you will have to decide what the best course of action is for him and you. My heart goes out to you.