Rights of a wife whose American citizen husband impregnated another woman

Good day! I would greatly appreciate some legal advice about the problem of my close friend. Her husband is working in the US and is now an American Citizen. They were married here in the Philippines before her husband started working abroad. She is a housewife and her husband sends money to her every month. She recently discovered that for almost a year now he has been living in the US with another woman(also a Filipina) and that woman is now pregnant. Her husband stopped sending financial support to her and is threatening to file for divorce and withdraw her US immigrant visa petition.

My questions are:
1. How can she claim financial support from her American citizen husband? (she needs to buy maintenance medication for her heart ailment)
2. Can she file for a case against her husband and his mistress who is now pregnant with his child? If yes, is her husband still under the jurisdiction of the Philippine court?
3. Can her husband withdraw/stop her US visa petition? (she already passed the medical exams and interview)

Thank you and God bless.

my recommendation is that she seeks assistance by looking for an NGO which provides legal assistance in the USA.

the husband's acts are no longer within jurisdiction of Philippine courts.

Yes, the husband can withdraw the petition, and she would have to apply on her own.