The granddaddy of them all phrase informal mainly US
The largest, oldest, most remarkable, or most respected person, object, or thing of its type.
This company is the granddaddy of them all.
I have a collection of stamps. That stamp is the granddaddy of them all.
To be in a poor condition.
To be extremely old (a joke or a story)
To act or conduct oneself in an imposing, impressive, resolute, or manly manner or composure
Another individual is far older than the individual in question
To decide to believe someone‘s saying although they may not tell the truth
He said that he was late because he had an accident and I gave him the benefit of the doubt.