I have a divider in my tank.. we use the algae magnet and small filter to hold it on one side, and the pressure from the other filter is holding it back on the other side.. I dont know what else you can use....
He should recover without any major problems. Using Melafix will definitely speed the process. Hope everything works out. Also make sure the water parameters are good, but if you are doing regular water changes there shouldn't be any problems