It's going to be bad if it is shown to be true. But "helping Trump win", what does that mean? What, specifically, does "helping" mean in this situation?
Putin's strategy comes from the book Foundations Of Geopolitics by the ultra right wing political theorist Aleksandr Dugin. Dugin writes of the way Russia can essentially conquer the world. He says that America can never really be defeated, but that Russia should foment racist and isolationist politics to keep the country divided and to make it recede as a world power. Trump's candidacy must have seemed like a gift from God.
And FWIW, the plan for the UK was to separate it from the EU.