Thats just a fader. Ive raised bp for years and this is what you get when they fade alone, in a stressful environment. The color of the fade is dependant on those around the fish, and the brighter the color denotes how dominant the fish feels when it fades (as fading actually won't happen unless they can prove themselves somehow usually by fighting)
So by stressful environment, I don't mean theres anything wrong with your friends fish or tank, but that fish was probably raised with a large group of non-fading siblings. He would have had the urge to fade but not wanted to draw attention to himself by changing to a brighter shade, which would cause the other fish to fight with him.
That being said, your fish will probably not stay this way if you do something about it. The best way IME to get these guys to change color is to put them in a tank full of blood parrots. I once put a white parrot in with orange parrots and had it change orange in a day. However I also have a white faded RT cross right now that I'm keeping with red KKP, he has turned yellow, but is taking a while to turn orange. The fish that changed right away I put with 10 blood parrots, the fish that is taking a while to change is in with 4. I believe this is the reason.
So if you want it to turn red, just put it in with some "purple" red parrots