Veterans who find themself homeless include people who wore a uniform for six months. The military experience wasn't the dominant part of their life experience, but because they wore a uniform for six months, they're a veteran. You can just imagine any citizen who finds himself on the street and think about all the factors that led to that result. They're common to all citizens.
Those who are long-haul servers—for example, serving for two decades plus find themselves homeless a lot later than their civilian counterpart; they're almost 10 years older, I think, on average. Note that this is completely unscientific, so please treat this as anecdotal. Among those who had longer service, this is in part because they had a supportive military foundation that sustained them in their life up to retirement. Beyond that, they transitioned out and for whatever reasons—be they attributable to military service or not—they find themselves homeless. But they're typically older.
In some ways military service could be an aggravating factor for a mental health issue or an addiction or other injury acquired while serving. In other ways it could have mitigated and retarded that journey into homelessness. There's no one answer; there's no one thing. But I'd say that the fact that they served and the fact that we can connect with them as people who have served is an opportunity to reconnect and create a new connection that can help them get off the street.