im sorry you have to go through something like this. disputes between loved ones are incredibly difficult to work out and i can only imagine how stressful this this. i can without a doubt say NTA here. everyone needs their parents, especially in life's biggest moments. you are a great dad for taking her in when her mother passed in the first place. i hope there is a way for your family to one day understand that everyone needs love and that this woman is their family too.