I think we all knew in the back of our heads that this injury wasn't going to be 4 - 6 weeks. When any joint moves into such an irregular position there's going to be a lot of associated structures damaged. Just think of the muscle attachments around the knee joint - Gracilis, Sartorius, Biceps femoris, Semitendinosa, Semimembranosa, etc (upper leg muscles) all attach to the lower leg or there abouts and lower leg muscles such as Gastrocnemius and Plantaris attach to the upper leg (femur)....when you push all those muscles that far beyond it's normal range of motion you're going to be causing a lot of damage.
Now think inside the knee joint...inside the tibia, femur and patella and all of the ligaments associated with stabilising that joint...they're made to resist against minor movements exceeding range of motion....throw a leg that hard out of position and there will be some major tears happening. Forget the season...forget the first half of next season even...he'll have to go through a lot of rehab to get to walking let alone jogging, running, sprinting and strength training. It's very likely that he'll never be the same.
Good spot Frenzy for seeing through the post-match statements. I guess you're pessimistic attitude to everything has FINALLY gotten you somewhere!