It's called Acetabulo-Femoral hip impingement syndrome, it's a "fairly" new diagnosis in the sports medicine world. Commonly seen with young athletes
To clear things up:
1. AFI for the most part comes off as chronic pain (groin) with respect to rotation of the thigh as well as flexion
2. It has nothing to do with instability, so if you're worried about "his confidence", that's not really an issue........an athletes lack of confidence post-surgery is primarily relegated to ligament/tendon tears of their major joints (acl, mcl, Achilles,etc)
3. It's due to uneven gliding of the hip joint (which is a ball&socket) creating bone spurs, possible cartilage damage, +/- LT...... (Kind of like a piston slowly seizing in an engine, the motion becomes less and less fluid)
4. It is not major surgery, it's arthroscopic (3 inch incision) and involves removing the bony growths, removing any diseased cartilage (collateral damage from uneven joint rotation) , and repairing the labrum (which isn't always torn)
Personally, i see no reason to be overly concerned, full recovery in ~3 months, if anything he will have to regain his strength, but overall after the procedure, he should be 10 times more explosive, because an AFI will undoubtedly hold you back due to the pain it causes.
All in all, it's unfortunate he won't be able to work on his bball skills over a portion of the summer, like his peers, but if he was dealing with AFI for much of last season, the procedure he underwent will free him up towards becoming quicker and more explosive on the court...