He reigns for another few years before dying in his sixties. His rather cryptic plot to divide up the West into bite-sized fiefdoms between his younger sons goes ahead, with his eldest son Theodosius taking the East in its entirety. What happens next is anyone's guess. I suspect that the Persians will have a go the moment the news of Maurice's death reaches Ctesiphon, so Theodosius will have that on his plate for a few years. Presuming he's competent enough to hold them off, I expect he'll gobble up his remaining brothers.
Alternatively, Maurice is overthrown a year or two later, perhaps by Phokas, perhaps by Heraclius, perhaps by someone else entirely. He really was a paradox- a general practically undefeated in battle, who was hated by his troops.