You have written that an EMG, ECG and MRI was done in your fathers case. However, I am not sure whether MRI of the back or hip was done. In case, an MRI of the back was done the normal expression may mean it is normal for his age. This could include degenerative changes that occur with ageing and the pain may be because of the degenerative changes. I do not recommend injection Neurobion, particularly because he is a diabetic and there is a high probability of infection. In the absence of any other finding we can presume the pain is because of degenerative changes in the spine. This pain can be relieved with exercises and pain killers as and when required. You could take a second opinion from another orthopaedic surgeon.