Patrick Mouratoglou answered the question about new coach as below on his facebook
:"As you all know, Grigor Dimitrov is currently coachless. He doesn't want to rush and takes his time. He has a whole Team at the Academy working with him daily. At the moment, he is starting his pre-season preparation. I will help him for that period and his father too. When he'll be ready to find a new coach, we'll consider the options and take the decisions together."
Thus the coachless status may continue for a while until the suitable time but he has the whole academy team support