Are Pain Killers Advisable For Person Suffering With COPD?

My dad have COPD he came down with a cough and had a hard time bringing any up. His doctor gave him cough syrup with with codeine and gave him hydrocodone pills. His doc. Told him to take the syrup in the morning then take hydros through the day for his cough. I tried to tell him it was no good to take pain pills with COPD.