Potty training at night

Fortunately, my daughter was potty trained and night time potty training just followed. So I have no real experience. But, I have had a relative who went through this. She said that she would ask her son to hold it for a few minutes. If they’re at the store and he needs to potty, she’d finish what she was looking for on the aisle then make their way to the bathroom. If she was in the middle of doing something at home and he was playing and had to potty. She’d ask him to pick up a few toys before he went. She also would make sure he’d pee before he went to bed and no drinks 2-3 hours before bedtime

You generally dont night train as its linked to a hormone being released that makes your body from wetting itself in their sleep. It is very common for this not to kick in until age 4 to 6. Just be patience.
The whole thing of not letting your child drink hours before bed isn't very nice because what if your child is thirsty? Would you go to bed thirsty and then not drink for another 10+ hours. Its not healthy

You can't train it. They do it when ready. It's a hormonal change.

Leave him to sleep.