He has already said that, several times. Including once in a debate. This is not new.
As for your assumption about the mandate, I don't know enough about what they plan to do to comment.
Will they ask him about the mandate tomorrow? Seems like an obvious question to ask.
If he wants pre-existing conditions to be covered, he has to favor the mandate.
Otherwise, why would anybody have insurance? If I am guaranteed coverage no matter what happens to me, I can drop coverage until I get sick.
Then, because I can't be refused coverage, an insurance company has to cover my sickness. They can't refuse.
If Trump doesn't want the mandate, then how does he propose to make sure insurance companies are solvent?
If there's no mandate, no insurance company will be part of this.
Voila. The government has to cover the sickness, which makes the government the payer of record.
Single payer.