I don't get it
My mother is from Canada and came to the States when she married my dad in 1956. she's lived in the US for over 50 years, though she has never became a citizen, she did apply for permanent resadency. I'm not entirely sure how that works but she has to carry her card every where she goes.
Now, this is where I'm confused, if my mom never had to return to Canada after a certian number of years, why does your friend have to go back to Scotland? Why can't she renew her visa and greencard or apply for a permanent residency until she can gain citizenship?
Is your dad a United States citizen?