It's still not working if you go to his hideout BUT I triggered it when Xeroth was asleep, Rhot will be waiting for him then you have the talk option "Training" with Xeroth at his hideout after that I could finish the quest: "Sleeping Issues". The problem with this event is that he needs to oversleep and I think is badly implemented because when I was recreating* step by step what I previously did to trigger it Xeroth was awake and was with Rhot, maybe it's random I don't know.
*I was sleeping to 9:00 am on Saturday and was visiting Rhot who was waiting for Xeroth. I was loading previous saves before for the first time event: "Training" with Xeroth and Rhot will trigger, but it happened only once for me :/