No doubt about it - this grandad is a hero.
When his son sits him down to ask him how old he thinks he is, his Dad replies with 'I'm 79,' which is a full 19 years off his actual age.
They continue to play a guessing game with his age until they reach 98, with his son explaining, 'you're going to be 99 this summer and 100 next year.'
We should all just stop counting our age and mentally stay in our 20s forever.