Friedrich Wilhelm hated all his father loved: pomp, the French, and fancy food. He sold his father's horses, furniture and jewels; dismissed nearly all his courtiers. He lived as a country gentleman,
He had a few intimates, including the Prince of Anhalt-Dessau and Count von Grumkow. Little known is that he, too, suffered from porphyria, a disease causing terrible suffering and, when suffering his agonies, Friedrich Wilhelm became the terror of all in his presence. He would take his cane to anyone, breaking teeth and noses, roar "Love me" to passers-by and at the same time take his cane to them.
To counter his unhappiness he took to drink, most of the time in the company of his soldiers. All would get drunk and, mercilessly and often cruelly, tease the ever present Prof. Gundling. Friedrich Wilhelm collected the tallest of men for his grenadiers, paying a lot of money to obtain them, even by kidnapping, and acquired over 2,000.
Friedrich Wilhelm regulated the education of his son, Friedrich (II). No history before the 16th century was allowed unless it was in relation to the house of Hohenzollern; and no Latin, pronouncing that a lot of knowledge would only clutter his brains. Only those sciences connected with warfare were encouraged.
At first Friedrich Wilhelm loved his son, even to giving him his own regiment of 131 small children to drill. After a while his disease worsened as so did his temper. Friedrich, polite and delicate, was
beaten for wearing gloves in cold weather, and for eating with a silver fork. At first Friedrich was terrified of his rages but later became fascinated and, with his sister Wilhelmine, would tease him,
even going so far as to work him into a frenzy and then flee into their mother's apartment.
Friedrich Wilhelm began to prefer August Wilhelm, a son ten years younger than Friedrich, and Friedrich began to plot. Again the English marriages came to the fore. Friedrich Wilhelm was willing to send Wilhelmine to England but did not want an English bride for Friedrich.George II of England, however, was of the opinion that it should be either both marriages or neither.
The treatment of his son worsened so that Friedrich feared for his life. At one stage Friedrich became ill and appeared to be dying. Full of remorse, Friedrich Wilhelm hugged and kissed his son, but when Friedrich was recovering this knowledge was kept from Friedrich Wilhelm for as long as possible.

When Friedrich Wilhelm was away, Friedrich had a great time with his friends, Lieutenant Keith and Hans Hermann von Katte; but when Friedrich Wilhelm returned he sent Keith back to his regiment and Friedrich and Wilhelmine resumed the teasing of their father. In debt and greatly fearing his father, Friedrich wanted to escape. On a journey when Friedrich Wilhelm took his son with him, his son planned to escape via France to England and almost succeeded. However, a terrified page told Friedrich Wilhelm all and, after a terrifying scene, Friedrich was placed under guard, and Katte was arrested even though he had been warned to escape.
On his arrival at home, Friedrich Wilhelm beat and kicked Wilhelmine and locked her up. A girl who used to play the flute with Friedrich was publicly whipped; Katte was called into his presence and was beaten and kicked; Friedrich Wilhelm even wanted him tortured. Friedrich was imprisoned and interrogated. However, no admissions of desertions were extracted so that Friedrich Wilhelm did not know what to do. In the end Friedrich Wilhelm sentenced Katte to death because as an officer he had betrayed his king. Katte was taken to the castle where Friedrich was held captive and outside his window Katte was beheaded. A forthnight after Katte's death, Friedrich was taken to Kuestrin where he was to learn about local government.
By making life for his son as unpleasant and boring as possible, he forced Wilhelmine to accept the marriage proposal of a cousin completely unknown to her. Friedrich Wilhelm hoped this would restore peace within his family but his queen sulked. His next step was to have Friedrich married. The Emperor had opposed the English Princess Amelia but, when Friedrich was almost married to Elisabeth Christine of Brunswick-Wolfenbuettel, the Emperor changed his mind. In order to make an anti-French alliance, it would suit him if Friedrich married Amelia after all. Friedrich Wilhelm never forgave the Emperor this deceitful behaviour and the marriage of Friedrich and Elisabeth Christine took place.
His last years were filled with disappointment in the Emperor who took Friedrich Wilhelm for granted. As well, the childlessness of his crown prince worried him. Towards the end of his life his illness tormented him and he could no longer sleep. He spent all his time, day and night, making little wooden boxes. When courtiers thought the end was near, the crown prince was called. However, on arrival he found his father outside the palace. Contrary to the prince's expectations, Friedrich Wilhelm was delighted to see him. Moreover, his end was soon to come and he died re-conciled with his son.

Source: Leo van de Pas