Hurley makes the observation that Mercutio doesn't seem too into the whole fatherhood thing. Which of course means that his backstory is going to show that it was Walt's mother who took Walt away and married some guy named Bryan, who adopted Walt. Mercutio's all het up to go and get Walt back, but then he gets hit by a car, and winds up in a wheelchair. And we miss a large chunk of his life, so let's all assume this is the time he spent in Oswald maximum security prison, all right?
You see how that didn't make any sense if you didn't watch Lost last night? Start watching Lost, hoser. It's second only to Arrested Development on the list of network TV shows that don't make me roll my eyes.