Being the nerd that I am (for law stuff, since I'm a lawyer) this really interested me so I've looked into it a bit further. What I've found so far is that his conviction is basically wiped out, because he was in the midst of appealing it and died before the appeal could be heard, so the conviction doesn't survive his death. An odd rule, I've never heard of anything like that before. Not sure if that's common among various states - we definitely don't have that rule in Canada.
Anyway, even though the conviction is gone it doesn't mean that the victim's family's wrongful death law suit against him is doomed to failure. It just means it won't be as easy a process for them to get a judgment against him. With the conviction they easily could have won, probably on a summary basis even because there wouldn't really be any genuine issue for trial. But now, with the conviction gone the matter will probably have to go to trial. So what could have been dealt with within a couple of months will probably now end up taking a couple of years. However, it's not impossible. They'll basically need to try the case again to get a judge or jury in civil court to find that Hernandez caused Lloyd's death.
What's more intriguing is his estate may be able to resurrect a claim against the Patriots with the conviction gone. They fired him for just cause, meaning they wouldn't have to pay out his contract, said 'cause' being the murder of Lloyd. Without the conviction their basis for firing him his gone. It will be interesting to see if the Patriots can basically bring it's own variation of a wrongful death claim against his estate - not for damages, but to have a judge or jury in a civil court make the determination that he caused Lloyd's death, allowing the Pats to get out of honoring his contract.
Interesting stuff.