If i had fex a thai gf and i died my embassy will get notified right away.About my kids in my country they will get all i had.Money..properties etc.Thats the law.My thai gf wouldn't get anything.Be aware if u die and she use ur ATM card after she will be in big trouble the day they find out that.There been some cases that the foreigner have died and the thai wife not noticed the embassy and still receive pension from the decided get arrested.
In this days its not easy to do like that.The thai police will notify ur embassy and they take it from there.