i am very sorry for your pain... This is a big loss and it is understandable how you feel abandoned... but, I hope you consider changing your perspective on it and I hope that altering the way you interpret this situation will be part of your grieving and healing process. I am saying this because I do not think your flatmate banished you; he just went through something terrible and he is drowning in his own drama hence he is making decisions towards recovery. If moving out of the apt is going to make him recover faster, he will do that. Additionally, you, as a loving and a caring friend, may consider wishing the best for him and not take his actions personally. Because they are not... he is trying to recover. This is about him and it is not about you.