Will I get in-state tuition if I take a gap year?

In some states, this can work. In others, it can’t.

In some states, this would work for community colleges.

What is your family situation that your mom is living in a different country and your dad is lost?

If you are a US citizen or legal permanent resident alien, and your mom is not in that status and lives outside the US, and your dad is completely missing, then living with a family friend or another relative who is in the US legally could make good sense. You could live with that person while you get a job here and get your life sorted out.