I had a triple bypass in 2007, aged just 46. I can tell you that after 4 weeks I was in a LOT of discomfort. It wasn't until three months that the pains started to become bearable. Every day for those three months I wished I had never had the surgery. Even getting in and out of bed was agonising, causing me to feel nauseous and sweat with the pains. After three months I was able to do gentle exercises, such as gentle chest stretching etc and this seemed to speed things up a bit. After exactly 12 months, there was no more pains.
If your husband is still experiencing symptoms that have persisted following open heart surgery, I would advise you to have him followed up by his surgeon or cardiologist to ensure that there is not anything concerning going on. While it is normal to have some post-operative discomfort related to the surgical procedure, any symptoms that have persisted this long or are new/worsening would best be served with a physical examination by a physician.