To answer your question I believe they will.
Now for how I really think you should do this. Let him eat as if he did not have type 1. would your restrict his dated at all? People with type 1 can eat what ever they want ( Ok maybe when they are very hight and are not sure why might not be the best time to eat 5 cookies,) with all the walking excitement I have a hard time staying above 100 let alone 70 and this is what a lot less insulin, not bolusing for meals, So with this said I would let him eat what he wants and just cover it ( I hope you are doing an I to C) also if he is newly DX I would talk to his dr about this trip and ask them if you should changehis does due to all the walking excitment and such.
another note bring extra of everything test strips, whatever you use to treat lows, Extra