Hi,
This case indicates to me that a brachial plexus / Cx nerve root traction injury may be the problem. Check the Cx and have scans organised, eg MRI if possible. If the patient has a nerve traction injury, recovery will vary dependent upon severity of injury. CRPS can develop as well, complicating the situation. If the above problems are confirmed, supportive treatment to maximise gains as nerve function returns can be maintained. Good luck
MrPhysio+