My 3m Old Son Died Two Months Ago And The

My 3m old son died two months ago and the cause is still undetermined. He had gastroesophageal reflux and was taking ranitidine. When my bf found him unresponsive he tried to do CPR and my son spit out black fluid from his mouth. My question is what would cause this and does the meds he was taking and his condition have any factor in his death?