On Oxygen. Should She Stay Away From Heaters?

Yes, mother is on oxygen, 2%, it s a concentrator in her bedroom. We have natural gas, so we have a wall heater in the bathroom, large space heater in the livingroom and our stove in the kitchen. The tubing that we have for the concentrator is a short one for when she goes to bed and 25ft one that reaches to the living room and back door. Mother sometimes eats in the living close to the large heater. I understand that natural and oxygen are dangerous. Should my mother not have the oxygen on in the living room when eating....we got our first cold front (52 degrees) and we do need to light the heaters? Please advise. Thank you.