The situation is that my character's (British) father divorced his mother when he was four and married an American lady, who he now lives with in California, two years later. As far as I understand the father would be granted permanent resident status on his marriage and would be able to apply for citizenship after three years. What I'd like to know is once his father becomes a US citizen would my character (a minor) be eligible to become a permanent resident? If so then how long would such a process typically take? Would he actually have to reside in the country for a specific amount of time or could it be done while he was living with his mother back in the UK?
Apologies if these are all really obvious questions but my head is spinning right now.