NEW YORK — A top executive at former President Donald Trump’s family business pleaded guilty Thursday to evading taxes in a deal that could potentially make him a star witness against the company at a fall trial. Trump Organization CFO Allen Weisselberg pleaded guilty to all 15 of the charges he faced in the case. In a low, somewhat hoarse voice, he admitted taking in over $1.7 million worth of untaxed perks — including school tuition for his grandchildren, free rent for a Manhattan apartment and lease payments for a luxury car — and explicitly keeping some of the plums off the books. [time-brightcove not-tgx=”true”] Judge Juan Manuel Merchan agreed to sentence Weisselberg to five months’ incarceration at New York City’s Rikers Island jail complex, although he will be eligible for release much earlier if he behaves well behind bars.