What Are The Chances To Recover From Dermatomyositis?

My dad was diagnosed 3 months ago with dermatomyositis and he is 52 years of age. I am only 20 years old and It's really hard to cope with everything. I was just curious on what the chances are of him fully recovering or what the chances of him of dieing are. I feel as if he is keeping some information away from me. Thanks to anyone who helps.