As previously, Sullivan was supposed to attack Cena and take him out of the Royal Rumble. Cena would have taken time away from WWE and returned to set up the match with Sullivan at WrestleMania. In reality, Cena's time off is because he is about to start filming another movie.
During the NXT TakeOver: Phoenix conference call, Triple H said that nothing has changed with Sullivan. That doesn't necessarily mean that the Sullivan vs. Cena match is still on but Dave Meltzer reported that Sullivan was told that they are ready to have him back when he's ready.
The feeling on him with management is that he is money and they are understanding of his situation. A decade ago, they may have handled the situation differently but they have been much more understanding about mental health issues especially after learning about what Mauro Ranallo deals with.