His Dad was a volunteer fireman, which was dangerous job, so he ( ) his Dad a lot

根据提供的参考资料123457，可以确定空白处应填入的短语是 "looked up to"。这个短语意味着他非常尊敬和钦佩他的父亲。因此，完整的句子是：

His Dad was a volunteer fireman, which was a dangerous job, so he looked up to his Dad a lot.123457