Is the client communicative? Does he have any voluntary control of his movements? Can he follow simple instructions?
What is your skill set? Are you trained in active therapies (i.e. Muscle Energy Technique, Proprioceptive Neuromuscular Facilitation, Active Isolated Stretching, Feldenkrais, etc.)?
Passive massage and passive range of motion work may make this client's discomfort more bearable, but will have limited impact upon his ability to function. Active therapies are needed to engage his motor cortex to improve neuromuscular function. Further, he needs to know how to work on it himself, using skills he is capable of learning.
Depending on your current skill set, you may need to start studying the nervous system and learn some new ways to work with him. Consider bringing in another therapist with significant experience in active therapies. Observe them at work with the client and see how it goes. If the client is okay with this, it might be a great experience for both of you. (NOTE: The client would pay only the other therapist; as an observer, your time should be free.)