Weld seems to change politics as often as I change my underwear.
That said, I know a few Republicans who have said they would vote for Biden if he is the Democrat nominee. Whether they would vote for Warren or any of the other radicals, I don't know. I heard some time back there was a social media effort to get Republican voters to vote for Biden. Many think he would be a somewhat more benign president than the rest of the Dem contenders and they could live with that. The problem, as I see it, is that the radical lefties have take over the Democrat party and if Biden was elected, he could be forced by the radicals to become one of them. Certainly, if the Dems end up with both houses of congress and pass legislation enacting their agenda --Medicare for All, gun confiscation, etc. -- Biden would be compelled to sign it. Biden would not be as benign as these Republicans think.