Losing a sibling

My brother was killed in a fatal accident on January 23, 2021 and my family and I buried him on the 5 of February. When I found out that he passed away I didn't believe the news but once I saw his body inside of the confin reality sunked in. The mortician had to fixed his body up because my brother was involved in a horrific accident. When I glanced at my brother body I couldn't fathom what I was seeing because that wasn't how my brother appeared the last time I saw him. I began to have an anxiety attack to the point that I walked out of the funeral home for a fresh breath of air. To make a long story short, after his funeral I began to have nightmares of him dying and his eyes rolling in the back of his head and of me attending his funeral and he's chained to a confin and he wakes up during his funeral begging me to help him. My anxiety has intensified since his death and its difficult for me to enjoy life. I can't work or go outside without having an anxiety attack.