Look first off
Make sure your temps and humidity are CORRECT
Leave him alone for a week.
Get him eating on live for a few times for ya
Then you can try the switch to f/t
But keep in mind the first and second thing i said. These lead to stress. And stress leads to not eating
Edit: And as far as holding. IMO i think it's just stupid to hold a new snake who you haven't gotten to eat. Snakes don't like to be held they tolerate it. And if he is stressed out and not eating for you lets not add more to it
Edit x2:Also if u got a digital scale u could see how many grams he is and feed him 10-15% if his body weight if hes under like 1000g's i think.