dear sir ,
u are dad maight be suffering from frozen shoulder(adhesive capsulitis )
as he is 60year old with
diabetes...
Pls consult orthopaedic & Arthroscopy surgeon..
till that do hot water formentation and Joint Range of motion excericises..
Next Steps
for further detail u can consult me on chat or in clinic (ghatkopar/andheri)
or u can see another similar doctor
needs to be treated
thank u