How to file a case against My father

Hi hope you can help me or give me idea how to begin our battle. My mother is emotional abused by my father. He is a seaman for over 20yrs now. We found out that he has a mistress. We know the name of the girl. plan ng mother ko mag ask nang help sa POAE or any public lawyer kasi financially incapable na kami to hire some private lawyer kasi nag stop na ang father ko mag send nang money. they are legally married and my mother has a proof on the documents. ang mahirap lang is puro text massages lang and picture together of my father and his mistress ang meron kami. we don't plan to sue him on anything but we just need him out of his work. na sana hindi na siya makapag ibang bansa and in that way patas ang laban and we can live separately. Is it possible? how can we start it from here? saan kami dudulog at anu ang dapat namin ehanda?

Thank you po. God bless...

infidelity does not lead to loss of job. if he is not providing support, a case of economic abuse under RA 9262 may be the best bet