Does a POA mean that I can be banned from seeing my dying grandmother?

I am a 23 year old granddaughter who has her life in order and has done nothing but love my grandmother. My family simply does not like my choices in life because they are jealous and can not stand that i love and date someone different than them (he treats me very well). They are trying to ban me from seeing my dying grandmother in the hospital and trying to ban me from going to her funeral all because my uncle is her POA. This man has done nothing but wrong by my grandmother and all i want to do is go visit with her on her last days. My uncle has a major drug problem and along with that comes financial problems, as in taking money from my grandmother, threatening her and making her deathly afraid of her own son. He has manipulated everyone into thinking he has the power and is right including my own mother that gave birth to me. I have a great job and am starting my life and as i see it they wanted to make nice with me so i can be their money source and follow by their rules and they want to basically control my life and how i live it. Could someone please help answer my question with the best advice that could be given?