Pleurodesis is just a procedure to stick two pleural surface with each other so that there is no fresh formation of pleural fluid.
If he has massive effusion making him breathless there are two options:
1: put chest tube and do pleurodesis, this will make him relieve his symptoms of breathlessness.
It takes two to three for entire process in hospital.
2: go for in dewelling pleural catheter (IPC)
Not much complications for pleurodesis.