Wordy Puzzle

In this puzzle, the speaker mentions not having any brothers and sisters, so they are an only child. They talk about a man, and mention that he is their father's son. This shows that the speaker is a man. However, if the aforementioned is this man's father's son, then he is talking about himself, since he has no brothers (his father only has one son)! But who is the speaker talking about? Well, that "man's father" is him! That leads me to conclude that "that man" is none other than the speaker's son.

This puzzle is interesting as it uses language unfamiliar to everyday life. It uses three different generations of people: father, man, and son. It makes you translate what "man's father" and "father's son" mean in this context, in relation to the speaker.