Climate change doesn't make weather warmer, it makes weather more extreme.
they could use a warm coat.
Central heating is modern thing. It is good to have but not vital.
If you don't want to essentially demolish such a house next spring, you definitely need to provide at least a minimum of heat to the entire house and as you can't exactly do campfires inside you have to centrally heat it.
Central heating predates Hygene, Doctors and toilets. Try living without those, hope you don't mind the plague