Are BGLOs open to foreigners?

[PhDiva]

My fiance is a Black Brit and has mentioned more than once, his interest in Black fraternities. He asked me if I knew if his being a resident alien (aka "A Green Card Holder") would prevent him from joining a Black fraternity. I told him I didn't know but would post on the board I frequent. He's been stateside for 10 years, has a degree and has done community service. Would anyone happen to know if there is a citizenship requirement for BGLOs?

Thanks for any assistance,

PhDiva