Severe Pain. Treatment. please suggest.

My father has been diagnosed with Lumbar spondylosis.Diffuse disc bulge at L3-4 Level causing indentation of thecal sac and narrowing of bilateral lateral recess with no significant foraminal compromise.Degenerative Grade I anterolisthesis of L4 over L5 with pseudo diffuse disc bulge and posterocentral protrusion causing indentation of thecal sac and narrowing of bilateral lateral recess with mild compromise of bilateral neural foramina, indenting exiting L4 nerve roots.Associated facetal arthrosis is noted that further contributes towards secondary canal stenosis. Mild diffuse disc bulge at L5-S1 level effacing epidural fat with no significant foraminal compromise. He is in severe pain and loosing his appetite gradually. I am not sure where to take him and what should be course of treatment. Please suggest.