This ^^^. If he needs to toilet overnight, its is setting back his toilet training if you dont take him out. He cant hold on overnight so it is actually unfair of you to put him in a position where he has to soil his sleeping place. The more you set him up for success, the faster toilet training will come together. Aim for EVERY toilet being outside so you can praise and reward. Toilet training happens when two things come together - the ability to hold his bladder and bowel, along with the desire to do so to earn the lovely reward you give for outside toilets.