The analyses of a text #2

The protagonist, Philip, who was born with a club foot, moved in with his uncle Mr. Carey after his mother's death.
He goes to King's School at Tercanbury.
The headmaster Tom Perkins was a student of the present masters.
He thinks highly of general information, what with Philip's rich general information, he thinks of him as smart.
But Philip's master Mr. Gordon hates him for some reason.

...........................
The master seized the arms of his chair and grasped them as though to prevent himself from falling upon Philip. They knew that in past days he often used to seize boys by the throat till they almost choked. The veins in his forehead stood out and his face grew dark and threatening. He was a man insane. Philip had known the passage perfectly the day before, but now he could remember nothing.
"I don't know it," he gasped.
"Why don't you it? Let's take the words one by one. We'll soon see if you don't it."
Philip stood silent, very white, trembling a little, with his head bent down on the book. The master's breathing almost stertorous.
"The headmaster says you're clever. I don't how he sees it. General information." He laughed savagely. "I don't what they put you in his form for "Blockhead."
[Of Human Bondage by Somerset Maugham]
1. I can't find the object of "what."
So, I was wondering if a preposition is omitted before "what."
2. I'd like to know what "they" refers to.
3. I'd like to know what "his form for Blockhead" means.