Of course no end of yelling and screaming from their parents won't work - yelling and screaming at a five year old is not the way to go. Separate their bedtimes and make sure the five year old always has the same bedtime, routine is essntial to security. The problem here is that the five year old is insecure because of all the past problems and shouting and punishing will only make that worse. Make sure there is a set bedtime routine - supper, bathtime with lots of bubbles and fun and games, into bed and a storytime. settle him down properly with a story, read him to sleep if necessary, give him his own personal secure bedtime and put the seven year old to bed an hour or so later once his brother is asleep. Family councelling may really be necessary, not just because of the bedtime thing but because there is obviously a lack of parenting skill and insecurities to be resolved.