I'm the youngest so can't relate to younger siblings drying up before me but I was for quite awhile the only bedwetter in the house. My older brother and middle sister both stopped when they were 6 or 7ish, but I had issues until I was 14.
My accidents were pretty matter-of-factly handled; teasing wasn't tolerated. My Mom was very supportive and as sly as possible to help me keep it a secret around friends and distant family, she really helped me survive those years, but it was still pretty rough and embarrassing at times.
My older brother (oldest child) would whine whenever we went on vacation or to travel meets where we had to share a bed, me and him would share and then my sisters shared a bed Mom and Dad in their own room/bed depending on the hotel. He would always whine about sharing with me and then tell me not to pee that night but I can't remember ever leaking or anything like that while sharing a bed so I dunno what his fuss was about? Probably just trying to be annoying or I guess not wanting to get peed on lol but I don't think that ever happened that I can remember?