Him returning really doesn't show he didn't have a high ankle sprain. I think people really don't understand that a sprain of any kind is on a spectrum and the "timelines" provided are very general and not always consistent from person to person and the varying severity of the sprain. For example a grade 2 sprain or partial tear can essentially mean ~10% of the ligament is torn, or it can mean 90% of the ligament is torn, and the healing timelines for those are going to be drastically different.
So my guess is he had a high ankle sprain (or a deltoid ligament sprain, albeit less likely in a skate) and the imaging showed there was no significant damage (grade 1 sprain), but his ankle was quite swollen the first couple days and so they put out a "typical" recovery timeline, and then the swelling went down, the pain improved, the function came back, and because there was likely nothing overly concerning on the imaging he's deemed safe to play because his symptoms resolved. That is how rehab actually works in cases where there is not enough structural damage to something that it is deemed risky to play through. You return when your symptoms improve and when you can perform physical demands of your sport without aggravating it.