That is effectively what he said when according to the Washington Post he claimed that "he has spoken to his own accountant about the tax plan and that he would be a 'big loser' if the deal is approved as written." Of course, we don't know exactly what Mr. Trump's tax returns look like since he lied about releasing them once an audit was completed, but based on the one return that was made public, the plan looks like it was written to reduce his tax liability.
It reduces the tax rate for high-income people on income from pass-through corporations, which was pretty much all of Trump's income on his return. It also eliminates the alternative minimum tax, which Trump had to pay for 2005. And it eliminates the estate tax, which Trump's estate would almost certainly have to pay when he dies. In addition, it leaves in place a number of special tax breaks for the real estate sector, even as it eliminates them for other businesses.
It seems likely that either Mr. Trump's accountant is incompetent or Trump lied about what they told him about the impact of the tax plan on his finances.