The juice of a slice of lemon is fine for Pitta types, vinegar on the other can aggrevate them. You could the muscle test on your husband to show him the difference between the two.
Both lemon and honey have cleansing properties, if combined and taken with warm water first thing in the morning. Honey is bacteria-static and removes germs, and lemon helps to remove the waste that attracts them. If the tongue is coated in the morning, it shows that the GI lining has a similar coating. Bacteria tend to polulate there to help break down some of it. The drink assists in the removal of both the coating and the germs.