The first thing the son wants to know is why Father William has the habit of standing on his head; he questions whether it is appropriate for his father to do such a thing at his advanced age.
Father William replies that, in the past, he had reservations about standing on his head; then, he had feared that such a practice would injure his brain. However, at present, he has concluded that he will indulge in the practice since he is without the necessary organ after all.
The son continues to ask three more questions (four in all); however, his father tells him that he has already answered three and insists that those should suffice. This poem, Father William, is found in Chapter V: Advice From A Caterpillar in Alice's Adventures In Wonderland. In the story, Alice tells the caterpillar that she cannot seem to remember things as well as she used to. The caterpillar then tells her to recite the poem Father William. After she has done so, the caterpillar proceeds to tell Alice that she has gotten the whole poem wrong from beginning to end. This is telling because the poem itself is Lewis Carroll's parody of Robert Southey's poem The Old Man's Comforts And How He Gained Them.