Where he currently lives......Honestly, maybe he needs to consider self-deporting else he could be on their radar after you submit an I-130 or I-485. The I-485 will be denied since he was never inspected. I think the I-130 is useless in this situation as he, likely, cannot attain a Green Card for a long time (if he leaves the US, he will get a 10 year ban as it sounds like he has been here for years).