You will have to show that your health problems are causally linked to your contact with certain environmental hazards while serving in the military.
Also, I need to find out about this Medical Care Benefits, he also thinks he got sick because of asbestos besides the weapons, so is that possible?
Yes, there is a possibility he may have had contact with asbestos while working in certain military jobs. Asbestos toxic fibers were once used in many buildings and products.
Regarding VA disability benefits, what if during my military service I was exposed to a hazardous particulate material that has caused my asthma?