I smell something fishy in this approach because they will not have the same effect as the US buying Bitcoin directly, and I think Trump seems to be evading doing that. This is just my thinking.... instead of lending money to people and asking them to pay back in Bitcoin, why not buy the Bitcoin directly? How long will the money stay before they pay back, one year, two, or even ten years? Will Trump be in office when that money will be paid back? Something is definitely not clear with this statement.
It's not a totally whack idea from where Trump sits POV. You lend people dollars and they pay back in Bitcoin. Fine. But they now have dollars which they have to spend which eventually pretty much have to end up buying stuff from the US anyway. So win-win for the US and may be a way to extend dollar hegemony beyond the ever-shaky looking petro-dollar. Now, whether it would fly is another question...