From what I know of adhesive capsulitis (frozen shoulder) it takes between 12-18 months to improve and at times it can take longer. Generally a physical therapist treats the individual with frozen shoulder.
Mobility is severely restricted. There is much the individual with the condition cannot do. Hence the focus ought to be on improving range of motion and flexibility. Vigorous stretching is recommended, strengthening of the posterior shoulder girdle and the rotator cuff is recommended as well as performing the pendulum exercise in order to increase subacromial space.