I just finished reading all the threads about Braveheart and you and he have been through so much in the past few months. I'm so sorry that the tests have come back with results that are not good.
One thing is for sure, you have given him everything possible and considering what he was facing before you brought him into your home, it is so much. He is loved and cared for by you and has the company of your other cats, you guys are his family.
I hope that however many days he has left, that each one has a good moment in it. I really liked what you wrote in one of your posts in the beginning of February and it shows such kindness that he needed so much:

"His favorite thing is a good chin scritchie! (needless to say, he get those all the time) I have been cradling him on my lap to feed him. I rub the top of his beautiful head and tell him how wonderful he is."

I'm so glad he found you.