I keep having this reoccurring dream and have no clue..?

I keep dreaming about my dead ex brother in law. He is always happy except once. He never speaks but he is always smiling.. He ped a year ago at the age of 20 in a horrific accident. He was basically cut in half and bleed out before dying. He had just changed his life where he stopped drinking and was going to get married in 20 days when it accrued. I knew him since he was 15. Why do I dream about him? I often think of him on a daily basis. Sometimes I think I see him in a crowd of people or ping by.