You appear to have a good tale here. Personally, I would like to be 'seduced' a bit more with less information thrown onto the first page and a slower buildup as to why he died, The shift in viewpoint in the first paragraph distracted me from the strength of your opening sentence, which is very strong. I would stay in the narrator's head, showing more than telling.
One person can't tell another what to write but here's how I would edit this first paragraph:
"My brother’s death hit me like a gun shot to an open wound; it destroyed every ounce of joy my family had last year. His body was found washed up at the beach a few days after he was reported missing, and he spent his last few moments doing what he loved most, swimming. I remember him saying that even though he was drowning in debt, he could always swim and drown his sorrows in water instead of alcohol. A regular baptism, he would say. He had hoped his wrongdoings would be cleansed and washed away by the water, swimming was as easy as breathing to him. I didn’t think the very thing that gave life to his dying spirit would ultimately lead to his death."
"My brother often said he preferred to drown his sorrows in water rather than alcohol. When his body washed up at the beach, a few days after we reported him missing, I supposed he'd done just that; a final baptism, his wrongdoings cleansed and washed away with my family's joy. His death hit me like a gun shot."
Keep working on this. It's a good and poignant beginning. Maybe in the next paragraph there can be more said about his love for swimming and slowly show the reader why he was in debt.
On my own novel, I probably have cut as many words as I have written! On my 4th draft and still finding better ways to paint the picture.