Just because he was QB coach under Brian Daboll doesn't mean he is going to automatically run the same scheme as him. I'm sure it will be similar, but I have a feeling he will want to make his own mark and put his own wrinkle on things.
If I'm the Texans and the Patriots are willing to trade me their brand new, young QB, then I don't take that trade because it tells me they don't believe in Mac Jones nor think he is any good.