BEIRUT—A Syrian mother and her three children died in their sleep after inhaling toxic fumes from burning coal to heat their room in a village in southern Lebanon, a rescue group said Sunday. Youssef al-Dor, an official with Resala Health Ambulance Association, said he transported the bodies to be buried from a hospital where the four were pronounced dead. Al-Dor said the family used coal to warm their room on a cold night in a house in Kharayab, a southern village overlooking the Mediterranean Sea. Lebanon’s state National News Agency said the four died in their home. Lebanon, a country of 6 million people, is home to 1.5 million Syrians who fled the now decade-old civil war in their country. They often live in squalid camps and shoddy homes. As Lebanon grapples with an unprecedented economic crisis, poverty has deepened for both Lebanese and Syrians. The United Nations estimates that …