A lot of people have been touched by alcohol in their lives, which is at least part of the reason why these threads are sensitive. The circumstances of Brent's arrest and Jerry's death are what they are and people aren't going to change their minds about them at this late date. The reality of that score is, though, that the legal obligations have been met--or will be met very soon.
The moral question of whether or not the Cowboys should want Brent back is moot, as they've already said they're open to it. I will say, as I always do on the topic that Brent obviously bears a ton of responsibility for what happened. Let's also not forget, though, that Brown got in the car with a driver he knew had been drinking, and then sat through a high-speed ride in very dangerous circumstances without bothering to put his safety belt on. His judgement might have been worse than Brent's given that he wasn't as impaired. He's just, tragically, not around to accept his share of the responsibility.
The only open football question is whether or not this is a guy with the makeup to be on your team given what you've expressed you look for in players for your roster. Physically, he definitely was, but it's an open question whether that's still the case after a year and change off. Mentally, if he's got a dependency issue, he's not fit to take up a spot. Emotionally, if he no longer has the fire, or if the ordeal essentially broke him as a player, that would disqualify him, too. All you can really do at this point is bring the guy in and see where he's at and then make your decision based off of whether or not he can produce in a try out. And I'm sure that's what ends up happening.