Mind you, it’s impossible to achieve fluency in English through any other language. Absolutely impossible. For example, let’s say a Frenchman keeps on listening to (or reading) instructions in French on how to speak Russian. What do you think will improve from this training thro’ French? His French itself — or his Russian?
Of course, absolute beginners would find teaching done thro’ their mother tongue helpful — to learn certain basic facts about the English language. But not people who already know good English... and are trying to pick up fluency — the skill of actively using it with ease! No, bilingual effort can’t bring fluency!