My 4-year-old still needs a pull up at!

Moms, I need some help. My 4 almost 5 year old HAS to wear a pull-up at night still. We stop anything to drink after 7:30pm and he uses the bathroom before he lays down. What should I do? He hates wearing them… He says “but my brother don’t have to wear them.” His little brother is 2 and is FULLY potty trained… HELP