It appears that either your husband doesn't want to quit smoking
or is too scared to do so. If he has a good rapport with his doctor, you can ask the doctor to explain to him the risks of smoking in his condition and to advise him to quit. If this doesn't work, you can take him through the information available on the net about the harms of smoking. If he is scared of what will happen after quitting, reassure him that quitting is uncomfortable but not life-threatening. Tell him it will just be like having a mild attack of flu
and will get better in a few days. There are medications to help him quit smoking, so he need not be scared.