Anything could be going on here insurance wise. The VA definitely sometimes denies claims that are not service related or because of preexisting conditions that were not evident at time of entry into service. So could be a denial of claim based on these sorts of VA technicalities. If he also has Medicare (which some veterans may not), Medicare can have huge copays depending on whether the insured has a Medicare Part B and a Medicare supplement policy or not. In other words, it is very plausible that there are significant uncovered expenses, but exactly why that’s the case could be any number of factors.