Spinal injury in lower back. Inputs!

Hi , my brother in law  has a bike accident almost 1 year back and at that time there was no major external injury, but there was some pain in the back at that time and later after treatment he got well, later after some time he travelled in a local bus in a very bad roads ,that causes again a bad pain in his left leg. We did a MRI and one of the doctor suggested that his there are cusions kind of thing in the back bone and one of them slightly in bad shape and that is blocking the nerves .and due to blockage of nerves you are in an extream pain. He suggested a surgery for the same , could anyone please suggest us if surgery is the only option or it can be treated with medicine and theripy. Attaching the snapshot of the MRI report. Greatful and eagerly waiting for your valuable inputs Thanks & Regards,