Hmm? His appearance depends solely on if you told him to train OR that he is fine the way he is/didn't see that question after he joins the tavern. The change is visible after you get back from the mountains.
...The "6 months" thing is the automatic time skip after completing the first part of the mountain and coming back, not actual in-game time. Your decision must be made before you depart for the mountain, the effects will be visible when you come back.
