Filipino Father seeking help with USA wife about their children?

Hi,
I'm asking for some guidance/advice. I have a male Filipino friend here in Angeles City with 4 children with an American woman who lives in America, he's married to her in the Philippines tand she has abandoned him and their children and has gone back and married another man in the USA. She is not a Philippines citizen just USA . It's a lot different because it's usually the other way around . She's never registered her kids as USA citizens and they should be. He gets no support from her and it just might be biligamy that she has gotten remarried without getting a divorce in the USA and now has more children there. They were married in the Philippines. Does anyone have suggestions or advice? Are there any pro bono Lawyers who might be interested. It seems he could get some social security at least for his kids or something. Thanks all. Past this on or PM me if you wish.

advise him to approach PAO if he is an indigent. However, even if he gets a court order for support, it cannot be executed if she is not in the Philippines.

Thank you