My Husband, Age 64 And Physically Quite Strong, Has Begun

My husband, age 64 and physically quite strong, has begun to make mum- mum- mum noises under his breath softly. This happens daily, most often in the evening when he is on a computer or stressing about something. He does not seem to realize that he is doing this, and can control it for a while when asked. He works as a commissioned salesperson and is depressed that he has two years left before he can retire. His normally cheerful self has been replaced by someone whose face lacks expression unless amused. He seems to have developed a hearing loss ( both his father and paternal grandfather were profoundly deaf in old age) and he becomes irate when he mishears someone. He goes to bed by 8 pm and rises by 6am, but often wakes during the night and is unable to fall back to sleep right away. He has no bad habits other than having 2-4 cans of beer upon coming home. His diet is good- plenty of fruits and vegetables, fish and chicken. His father died of advanced Parkinson's, but he shows no symptomatic changes (gait, tremors, etc. ) other than a change in facial expression. Please advise. Thank you.