Is the smell emanating from the mouth when he speaks or breathes or from his armpits or just all over? Metabolic disorders can cause unusual body odors. The best known of these disorders are trimethylaminuria and maple syrup urine disease (both of which are rare), and ketoacidosis, which is rather common, especially in poorly-managed or undiagnosed diabetics. Liver and kidney malfunctions can sometimes lead to an ammonia smell, and some infectious diseases have characteristic odors.
Having been around diabetics all my life, I suspect ketoacidosis which can lead to kidney problems. Have his blood and urine checked by a doctor to see if there are proteins in the urine and his A1C level. A1C should be between 5 & 7 in diabetics and the protein levels should be less than trace to rule out keto.


