Michael and Walt's departure from the island

Hi all,

I've been doing a rewatch and I've just finished S02E24.

Let's think about it. A father and son arrived in the U.S. 2 months after the 815 crash. And they started to live their "normal" life. Walt started to going school every day. He made friends at the school and started to get interacted with people. And nobody has ever noticed that the guy is one of the passengers of a flight that's been lost in the south pacific! No way.

I mean, how come nobody ever hasn't questioned them about the crash, plane, or anything? How did they manage to enter the US? Did they have fake passports? How did they manage to get fake passports without a penny?

I'd love to hear your theories