What you're seeing there is the shoulder sliding off the joint and in a downward position. It needs to be shoved back up and in. It's extremely painful but once it's back in place, it just sore for a few days. Acute injuries like this are much easier to treat than any chronic condition. In fact he should be back to 100%, which arguably for Julius isn't the 100% we need, but we'll put that aside for now.
The tear of a cartilage envelope around the shoulder, the labrum, makes the joint more likely to be unstable. But in Julius's case, it may not be significantly more unstable if he rehabs it and comes back this year. You strengthen and heal, and you get back stability. In other words, the labrum isn't necessarily needed for him to play without pain, but there are some risks of another subluxation involved, so sewing it back up is just safer.
He can perhaps do rehab now and surgery in the off-season, then come back by about the start of next year.
Unlike a ligament tear or a tendon tear, the cartilage tear of a labrum is not make or break. If it's not fully torn or unstable after he rehabs it, and he's got the advantage of a lot of muscle and professional PT, then he can play this season again and it may not affect his ability to play at 100%. There may be some risks, but then he can always get it sewn up later.
Problem is, if he has another injury, then you are getting into chronic versus acute. Two different partial tears at different times could be simply worse than him having a full tear now.
*RealGM is not a healthcare provider and is not qualified to give medical advice.