Yes, My Husband Is 59 And Has Always Been Healthy

Yes, my husband is 59 and has always been healthy up to this past years. He has been complaining of headaches, took him to a neurologists who advised that it was not migraines, then his primary dr. Advised us that his blood work showed that he was malnutrition, level of fat was at a 3.2 which the dr. Said that would be for and eighty yr old but that my husband levels should be at 4.5 or higher, and now I found out that he has protein in his blood. Do u know what could be causing all of this?