Something beyond me!

[Deepurple]

Dear Sir/Madam, would you kindly tell me the meaning of the underlined sentence? Thank you very much.

"A friend struggles with his teenage stepson, who shrugs as he helplessly explains his bad grades with 'I can't help it. I'm lazy. My father told me that I inherited it from him.' This teenager has taken his own difficulty in getting excited about geometry and, with the help of his father, turned it into a disease."

[shroob]

Dear Sir/Madam, would you kindly tell me the meaning of the underlined sentence? Thank you very much.

"A friend struggles with his teenage stepson, who shrugs as he helplessly explains his bad grades with 'I can't help it. I'm lazy. My father told me that I inherited it from him.' This teenager has taken his own difficulty in getting excited about geometry and, with the help of his father, turned it into a disease."

Not a teacher only a native.

The phrase means that the teenager finds it hard to connect with geometry, he struggles with it and doesn't find it interesting (hence his bad grades). Which he blames on his real father.