Hey there,
I am a 21 year old male, and I have a high alkaline phosphatase level in my blood stream. My doctor is stumped as to the cause. He has ruled out hepatitis since the alkaline level is not high enough for acute and my other enzymes are not affected, which rules out anything for chronic hepatitis. I feel fine though, and my doctor has said it probably is nothing to worry about, but just to keep on eye on it. Sometimes the body overproduces enzymes without any apparent reason. I would tell your husband not to stress about it, but to keep it in mind.
Some medications can cause elevated liver enzymes. Also, has he been tested for hepatitis?