My bf is killed in an accident and I lost contact with his family. How to find out where he is buried?

I had an internet based relationship for over a year. After my bf was missing for 4 months, I received a message from his email account written by his sister saying that my bf is killed in an accident. She subsequently closed that email account so I couldn't find out where is he buried. I want to see him one last time and tell him how much he means to me. how can I get contact with his family again and find out his cemetery?