My Wife's Best Friend Made Fun of Me, I Laughed, but My Wife Cried

My wife's male best friend has never had any sense of propriety and always takes vulgar jokes as her true nature. At my mother-in-law's funeral, he suddenly walked up to my dad and sighed in a fake voice: "Uncle, I'm sorry. Although auntie was fooling around with other dancers and cuckolding you, after all, she's dead, so forget it." As soon as the words fell, the eyes of all relatives and friends froze instantly. "No! You are mistaken, this is not-" I was about to explain that it was my mother-in-law who died, not my mother, but I was interrupted before I could finish my words. My dad was even more confused. He tried his best to explain but no one believed him. He was so angry that he died of a heart attack on the spot. Seeing that a life was lost, my wife's best friend reluctantly apologized. "I was just joking. Who knew his father wouldn't be able to tell the difference even if he is such an adult?" My wife was also there to help. "What Cheng said is not entirely groundless. Your mother is in her fifties. She is away from home all day long and goes out to dance. There must be something wrong." Am I angry?