My husband and I are struggling with our 3.5 year old son taking 1.5-2 hours to remain in bed at nighttime. He shares a room with his sister and this disrupts her sleep. He has been potty training for about 4 weeks now. He says he needs to go pee/poop and then goes to the potty. He does go pee/poop about 75% of the time. We feel torn b/c we want him to pee and poop on his own, as this is a struggle, but he needs to do it and go to bed! I get fed up after about 1.5 hours, so I lock the door to his room. Then, once he is asleep, I unlock it, so he can use the bathroom if needed later on or in the morning. How can we discipline the behavior without regressing in potty training?