What a mess! It goes to show how powerful malware is getting these days. Personally, I agree that he should get rid of everything and completely reformat his hard drive. I was, however, wondering if it'd be possible for you to ask your friend what his son was doing on the computer? Maybe it'd be a start if we knew what sites/downloads/content he's dealt with. I think that'd help a lot.
I wish you all the best, good luck.