Acute Shoulder Pain

My mother is 53 years old and she has been having severe pain in left shoulder while lifting.
She is able to do all other movements properly with her left hand other than lifting it up. she is feeling acute pain in shoulder joint while doing it. she is able to grip with the same hand.
She has undergone MRI test and the test result says -- "there is an osseous erosion noted at the lateral aspect of the head and the greater tuberosity of proximal left humerus. There is moderate to gross synovial effusion noted distending the left gleno-humeral joint space .There is is widening of the left glen-humeral joint space with minimal synovial and capsular prominence, abnormal T2W and PDW hyperintense to bright signal intensities are noted at the distal aspect of the rotator cuff tendons".
One doctor suggests only physiotherapy (My mother could not do it as the pain is unbearable), he does not suggest surgery. Opinion from other orthopedists suggest surgeries but they say the surgeries have 50% success rate.

Taking her age in to consideration and other medical problems (heart patient) in to account, I am really worried on what to do. I would be really grateful if experts on this forum can advise me on what should be my next step. Also kindly advise on types of surgeries available for treatment above problem,

Thank you all so much
Siva