Advice? Found out baby daddy has been hiding how much money he has and makes.

We just found out that the father of my friend’s kid has been lying about his assets and the money that he has. He has A TON of money and there is proof. His social media is private to try and hide some of the proof but he lives extremely extravagantly. He bought a luxury vehicle and goes on lavish vacations while my friend is driving a beat up truck and scraping by paycheck to paycheck without pushing for money from him. But recently we found out he has makes over six figures and more in stocks/bonds. His child support is $100 based on zero income and an agreement between them and now he just started giving an extra $380 a month. Our kids are the same age. They are teenagers. He literally just started the $380 a couple of months ago. Her kid already hates the dad because of his selfishness and will outright say it. He talks badly about how much she needs the money he gives. And then about her physically. All in front of their kid. Ugh. He’s just a deadbeat and narcissistic AH. But he has money. And they deserved better than his lies. She never pushed him for money in any way because she thought he was broke because that was how he presented himself to her and her family. Because we know the struggle life, she wanted to give him grace on his child support because he always said he had no money or he had to ask for money. WHICH WAS ALL A LIE.

Other than contacting a family lawyer and private investigator, does anyone have any experience or know of anyone that’s been in this situation? She can’t afford much so I’m doing a lot of research and investigating for her too before we go to court. But can she be owed based on when he started receiving this amount of money? The child support order has been open since her kid was born.

Child support is in CA but he lives in another state.