Gerunds are the same in form as participles except they take the form of nouns. An example of this would be "Working is hard" where working is a gerund that denotes that act of working, not the activity of working.
The sentence had repetitive words replaced with synonyms and pronouns. "but my father disliked..." is too much alike to "my father disliked" so it would get tedious and harder to read. They replaced it with "but he hated ... " to get some variation.
