Depression Support Group
Depression is a real and debilitating condition that is often misunderstood by family and friends. Its meaning can range from a prolonged period of sadness to an actual mental illness with specific symptoms. Find and share experiences with others who are going through the same struggles.
https://www.mayoclinic.org/diseases-conditions/depression/in-depth/depression/ART-20045943
http://www.psyweb.com/articles/depression/how-to-help-a-depressed-family-member
It's important to know that you'll be there if he needs you but also to give him space when he needs alone time.
It's a tough balancing act. It helps to re-assure him that if you'll always be there if he ever needs anyone to talk to.