I did the same (completely torn ACL, partially torn MCL, bone contusions) 5 weeks ago playing indoor football. I had ACL reconstruction surgery 3 weeks ago (using the petellar tendon). I am already beginning to jog and will never have to wear a knee brace.
Craig, I suggest your buddy sees a different doctor. I researched this quite extenisvely and know that other types of procedures (hamstring, cadaver) have much longer recovery periods and result in problems down the road (which I have seen happen with other friends). I will be able to get back on the water full force 4 months after surgery.
Make sure you see a "knee" specialist (not just and orthopedic surgeon) and make sure they commonly deal with athletes.
Let me know if you have any further questions. Also, check out the article on wakeworld: http://www.wakeworld.com/articles/2002/acl1.asp
Same surgery as mine. Good luck