In a true Wikipedia reference-linkfrozen shoulder there is very little flexion and abduction. So if your client has this then they do not have a frozen shoulder. Under arthroscopy the entire joint capsule looks read and inflamed. Not that the capsule of the shoulder joint has a significant amount of laxity and that is it not the capsule that holds the humeral head on the glenoid fossa. One need only look at a hemiplegic shoulder to see that. Other factors are in play here.

Most commonly people with suspected "frozen" shoulders are people with Wikipedia reference-linkrotator cuff lesions. Those should be investigated and treated as appropriate.