Wifes Father passes away and scammy girlfriend is after his money

its like a bad episode of whatever prime-time show you can think of.

My wife was estranged from her father. not by her choice. it was her mothers choice that kept her and her mentally disabled sister from her father. his family was very close and they would update him on his daughters and how they were doing throughout life - my wife played basketball through highschool and college and he had a little shrine to her sports career.

He had a history of drinking and mental illness most likely from the Vietnam War. he was never abusive to the girls when he was married to my mother-in-law. my wife and her sister reconnected to him, went to visit him in Las Vegas and it was good - he was happy and we planned regular trips but that never happened because he died a year later. he had a live-in girlfriend who is Filipino and was married once or twice before - they never married but it seemed a weird situation. even his death was weird but none of us were there, we think she had something to do with it.

he has some money and a house and a car in Las Vegas. he has told his cousin that he is very close to that he wanted to make sure his girls got that money because he was sick. he has no will that we know of and are now in a fight with this woman after his property and financials -- she forged a will and will not show anyone it. she changed some official documents saying she has a stake in his property -- we already paid $10,000 for a lawyer in Las Vegas to help us and she has a lawyer that keeps trying to get more and more - how can she have any stake in anything he owns? Especially private bank accounts

her name is not on any ownership of his house, car, or bank accounts.

the case is in probate now but it really makes me think that anyone can just contest anyones property after death to get it all.