TOEIC teaching

When I was in America, I hoped to be an English teacher after I go back to Japan.
But not an "English conversation teacher" as I am now, but a "TOEIC teacher."
Why? Because I thought I couldn't speak English very fluently, so teaching for exam (TOEIC) would be suitable for me!

For some reasons, I chose the English conversation school to work.
But since a few weeks ago, I started to teach a TOEIC preparation class which was my first desirous class.
The class is a private class. The student is Hiroshi, who is a sales manager of a foreign-affiliated company.

Hiroshi is a very smart guy, but in fact, (I'm afraid to say, though,) I think he is one of the "English learning refugees." He has been our student for ten years, but his TOEIC score hasn't been over 700.
I have never told him about this, but I know why he hasn't gotten out of the situation.

Reason#1: his shallow home study.
Reason#2: his cynical character.
I ain't speaking ill of him! Not only him, but also many students are satisfied with "the fact" that "I'm taking English classes!"
To be able to use English as you want, you need to take your time to think, read, listen, look up words in dictionary, etc. You need to "tread a thorny path" for awhile!
But Hiroshi doesn't take much time to study at home.
Also, he is always saying, "These words are translated into those meanings? You must be joking!" or "I don't think this English conversation makes sense!" etc, etc.
Once I explain a lot, he is convinced. However, the cynical attitude prevents him to improve in his English, I guess...
Actually, flexible people tend to improve in a foreign language soon.
Because they are to absorbed in practicing soon while cynical people are complaining.

Anyway, Hiroshi is a really nice guy, truly...
I want him to break the ice ceiling which has been soaring over him ten years.
I mean, I want him to get over at least 700 of the TOEIC score!

Can I do this? The beginning teacher's challenge has just started...
First of all, I need to change his character! Can I do that, for real???