No penalties assessed against any property owner or his property for failure to return property for taxation shall be remitted except by order of the Department of Revenue upon proof that the delinquent taxpayer was absent from the state and had no resident agent therein during the time for making returns of property for taxation, or when such taxpayer labors under the disabilities of minority, or is a lunatic, or upon proof made that he was unable, by reason of sickness, to make such return in the time required by law.