Pretty much what everyone has said so far is accurate. I spent a few years caddying there and could pretty much play the course in the dark (and nearly did every Monday where we were allowed to play) because it was so fun to play and watch other people play. I've planned to do a "Home Course" write-up with photos for awhile but haven't for whatever reason. This could be the reminder I needed.
The greens are great, and they tend to defy gravity like few other courses can, and I think I have figured out the reason why, something I would like to delve into further at a later date. Your friend may here something along the lines of "Everything breaks toward 13 Mile Road." This isn't entirely true of course, but it isn't a bad play if you are not sure what the line is. This is especially true for the southern portion of the course, mainly the front nine, that plays along a ridge valley. The rest of the greens are just hard to read (though they don't really look it) and require years of experience, if that. One bit of advice here--if possible, stay below the hole on both 2 and 9, and probably 12 too. Beyond the green is DEATH--they are that severe.
What may be better about the course than the famed greens is its routing. The site is really two different sites in one--a flattish plateau on the northern end that falls off into a ridge valley along the southern end, all in a nearly square shaped property. Ross's genius here is that he brought both nines into both geographic features. Furthermore, there is only one sequence where the holes do not change direction, between 12 and 13, but even there the wind effect still changes because 13 plays through a tunnel of dense mature oaks. I'm not going to say anything about 13. Let your friend experience it for himself without knowing what he is getting into. I remember my first time caddying on it, and I am glad I knew nothing about it. A cool, unusual golf hole, especially for Ross.
One more note, and it regards the restoration. This may be commonly known, but Ron Prichard did a restoration of the course in 2004. All bunkers were reshaped and deepened, some were eliminated, some were added. I support the shaping of them, for they reflect forms that could be natural on a silty clay soil. If they were built on sand like at Oakland Hills down the road, I might not be so giddy. I liked the bunkers that were taken out, but the ones that were added really only serve a sort of 'framing' purpose (I'm looking at you 7 and 18). Additionally, greens were enlarged, some fairways widened, irrigation rebuilt, and some trees removed, though not quite enough. Overall, I would call it successful work and something that I am grateful for happening. The Club did it right.
I have hundreds of photos but I'm choosing not to share them right now. Most great golf courses rely on great landforms, which almost never come out accurately in photographs. I say wait to experience it in person. The sense of scale of the elevation changes will be true, and all the little goofy humps and bumps and tilted greens of a 1920s golf course will come alive. If still keen, I can sort through and load some to photobucket, or you could do a google search. I think I have two images on my website too. I think firsthand in person is still the way to go though.
Hope he has a great time