Hi
@Edgecrusherr, I'm having exactly the same problem with a MBP8,3. It seems to me that dosdude1's GPU Disabler is causing the sleep and brightness issues, as the problem is happening on a clean install of High Sierra too, where no post install patches are required.
Have you fixed this yourself yet?
@dosdude1 I'm new to the forum and I've searched this thread but haven't found a solution yet. I really do appreciate your work on this but just want to see if you have a definitive answer on this?
Thanks in advance!