At what age can children go potty by themselves if they need to go in the middle of the night or early morning and then back to bed?

My son has been potty trained for a year, since he was 2.5 years old.

He has a Jack and Jill bathroom and I would love to let him just go pee on his own. I just don’t think he could deal with his underwear and pjs while sleepy. (He likes to take his underwear completely off before hopping up.)

*I should add, he’s on the shorter side so we’ve always just had him take off his bottoms and hop up facing the toilet. He is too short (and too clumsy) to keep his pants on around his ankles, use his step, turn around and sit facing the way a grown up does.