A client needs to file his last 5 years income tax but didn't work during those years. His last working year was 2012. He isn't a citizen but has a social for working purposes from DHS. Up until 2013 he lived in the states full time. Then 2013-2018 he was going back and forth and mainly spent his time outside of US. During that time he still had an address in US but wasn't physically there full time. He has to file his returns for legal purposes and was told to file a zero balance return for those years. Would he file a 1040 or 1040NR?