Jason

So I had a really good friend in high school who is no longer talking to me - and I don't know why. Soon after high school, he revealed to me that he has depression. I was supportive and felt honored that he could confide in me with such details about his personal life. We continued to be good friends for the next couple of months. At which point, we both left our hometown and decided to sign up for two years to go do service on missions outside the country. We got assigned to different places but still kept in touch. Part way through my mission, I found out that my friend had decided to give it up and go home - for reasons I am still unclear about. This is the point where he cut off all communication with me. When I finished my service, I came home to find out he had moved away. I talked with his parent and got his phone number. He answered once but when I invited him to go hang out with some mutual friends, he said he wasn't up to it. He never answered my phone calls again. I have found him on facebook and tried to add him as a friend. I have been to his parent's house asking for his address. I have tried instant messenger. I have tried everything I can think of to try and get through to him. It has been 4 years now since we have stopped talking. I still think of him and hope everything is okay. Is there anything more I could try? or should I just give up on my lost friend?