My elderly father is being financially taken advantage of by grandson & nephew. What do I need to do to stop this (daughter)?

Question Details: My dad's grandson almost took $100K from dad to invest in real estate. My nephew's (grandson) wife is now charging my dad $2,100 a month to take care of him in his home. This week my dad's convicted felon nephew took many of my dad's possessions. What step do I need to take before my dad has lost everyhting? He will need all of resources for his OWN care in the future. I live ten hours from my dad which make it hard to prevent him being manipulated. Important Notice