Happy Thanksgiving

My father has diabetic for 25 years and more and for one years he is on insulin , as for his eye check up for his spectacles ,we visited the eye doctor, he has advice to go to retina specialist for macular edema, Retina specialist has mention that his right eye is ok and left eye has only 10% vision left, as he conducted OCT and FA test after that he has said to go for laser in both the eyes and and if required for surgery, i want to know that it is good to go for laser and is right eye will be safe after laser and why is surgery required after laser , the right eye will be ok and the left eye vision 10% will be there or gone after this procedure I have OCT and FA film reports if you email is available i will send the films by mail,please give your opinion