No, he won’t. You’ve posted threads about this before, but seem to just ignore what you don’t want to hear.
Unless your friend is a spiritually powerful being, and has actually taken the time to build up his Body of Light/Rainbow Body/Body of Flames, he does not get to choose his next incarnation. He will not end up in the “astral realm” when he dies, but will return to Source because he has not bothered to actually Ascend.
This sounds like you’re being conned. You can make people sick, cause accidents, cause mental issues etc with magic but I highly doubt you’re going to be drawn into a vessel of some description. It’s not how spirits or magic works.
Well put. A necromancer could make use of your fading shade, but you’ll be dead and buried. He’d just be using some left over energy