Yes, he is a veteran in the sense he served in the armed forces, never in a war.
Best to contact a VSO (Veterans Service Officer)ASAP!
But he was exposed to chems he may not know about. Also hire a SS disability lawyer, a good one on the FRONT END, do not go through the gov’t’s red tape, you will be turned down repeatedly. and get him to working on getting your brother on Disability..it will help income wise if nothing else. Also qualifies him for Medicare A & B.
They kept a guy from my Sunday School class who was on the heart transplant list dangling for 3 years. So get the lawyer on the front end...they get 25% off the top, it is all they can get. And you get back pay from the day you file to the day you are approved. And your brother is going to need the income as the disease progresses. Medicare may be rationed health care but at least for now it is some help.