It's worth bearing in mind that Episode 2 takes place months after Episode 1 finishes (I seem to remember 3 months from the intro, but could be wrong), so presumably a lot has happened in that period that we haven't seen, including the survivors meeting other people along the way.
Before leaving the Motel, from conversations with Mark and the other survivors you learn that he came from an Air Force base, that he worked in the Commissary (which is where he'd been hiding), and that he had a large stockpile of food when he met up with our survivors, which he shared with the group when he moved to the Motel with them. That's what they'd been eating for the last 3(?) months, and is running out now, which is why Lilly has been rationing the food.
At some point in the conversations on the farm you find out that he (like Lilly) is ex-military (which explains why he was on the Air Force Base to start with).
*Spoilers* Other than that, he's a semi-interesting character, who's really only been introduced into this episode as a "red-shirt", which is odd as the series seems to be fairly happy killing off main-seeming characters who've been around for a few episodes, so I'm surprised they didn't use someone from Episode 1 for his fate, as that could have made it a bit more emotionally serious if we'd known him longer.