Good luck to all the torn meniscus turnbacks out there. I just had the ortho surgery myself (at 45 yrs of age) and the recovery was pretty easy. One day on crutches, light walking for a few days afterwards, and then just some PT to keep things stretched out (hammies, etc). Back up to full stride about 4 wks later.
My son was also a turnback last year (different type of knee problem) and unfortunately he was still not ready for this years BCT so he's opted instead to go the ROTC university route. Personally the depressing week long holding period he spent in the "lost squadron" there at AFA probably helped in that decision (i.e. he didn't want to go thru that again if he got pulled aside again). Too bad the AFA can't find a way to get injured cadets off campus faster as that period is ROUGH on them. Not only are the hurt cadets sitting around in an empty building, in an empty room, with little to do but wait for chow 3 x daily, but they may also be saddled with a roomie that's a sad-sack case (i.e. one of the cadets that decided on day one that the AFA was too tough or not for him/her, i.e. they went for mom-n-dad not themeselves, etc). That can be pretty depressing for those cadets that really wanted to be there but then got hurt... So if your kid is now in the "41st squadron" keep the letters & support flowing - they'll need the encouragement while they await the dozen or so signatures the turnback paperwork/file requires before they're scheduled for a flight home.
And as has been said her before, once they are home let 'em vent for a while but in the end you and they might find out that that extra year (especially with some community college experience/learning) was the best thing to happen to them....
Good luck to all MTB's - PM me if you need any advise on how things work during the "lost year".
PS: Keep in mind that since your cadet is now considered "active duty, extended leave" that they can be treated under Tircare, the Air Force Medical Plan. Just make sure your doc works with them - alot don't. You'll also need to get approval from a local base if you go that route. Also remind them that the military justice system controls them officially so if they really get into legal trouble (very doubtful ! !) they'll have more than the local police to deal with
So to keep em out of trouble, send em to the local movie theatre alot - they now get the military discount with thier ID cards