My dad was dying from cancer and his death sounds suspisious?

My dad was a Navy veteran and he was sick from cancer. We got mixed stories of how he died and it is suspicious to me. Before he died he told me he had a will and his current wife is now telling me that he doesn't have one.she is at the bar drinking with her friends and she had him cremated the day after he died.and she said she doesn't want to report his death to the military,and that she doesn't want a military head stone in the va seminary.She told my aunt that his heart gave out,but my brother that was there at the end said somehow he fell out of his stationary wheel chair and cut off his Oxygen and my step mom was the only one in the room with him.