By "sleep," do you mean the timer for shutting down the screen? If that's what you mean, both the timer and the brightness control still function on our early-2011 MBP 17. We
did not open our machine up to disable our dedicated GPU, so my advice is to find the correct terminal commands to permanently switch over to the integrated GPU that resides in your Intel CPU.
Please read this entire message before using the link I've inserted into this post...
After carefully reading this entire message, click
here to activate a link to a video showing a terminal fix for disabling the dedicated AMD GPU. The video is not of the highest quality, but it seems to cover everything you'll need to get the job done. Watch it a few times and take detailed notes before actually attempting the fix. The guy who made this video loves using commas to highlight certain words, so be careful to avoid them. For example, at about 4:18 into the video, you will see instructions to type in the text ,,reboot,, followed by pressing the enter key on your keyboard.
Do not type in the four commas! Instead, simply type in the word
reboot and then press the enter key. This should permanently disable the defective AMD GPU that came on the early-2011 MacBook Pros.
This is how we went about correcting this issue, but, needless to say, there are no guarantees when it comes to changing the instructions and/or command strings that your computer follows: so please proceed at your own risk. Most importantly, be extremely careful to type in the changes exactly as shown - except, of course, for the commas I warned you about.
Hope this helps your father.