Bell's Palsyter effect's af

My husband is 32 years old. He had a sudden bell's palsy attack on 30 december, 2009 on his right side of face. His work pressure was terrible all through the year. So he couldn't get enough rest. Though got treatment just after the attack and also took physiotherapy. He recovered a lot, but his right eye and mouth still not normal. When he drives, or talks, or eats for a long time, the eye looks smaller and he feels uneasy. Specially his mouth become lil stiff, he finds it hard to speak normally. What can be the reason? Is it curable?