Your description of the smell is same as for my husband. It follows him around also I can tell if he's come into room without seeing or hearing him.
He had had prostate cancer surgery 15 years ago and had radiation also which seemingly affected kidney. He has stage 4 kidney disease, and I am wondering if the this smell is being emitted because the kidneys do not function correctly. I read but have not tried that 2 drops of Peppermint oil on tongue would cover the smell.