J.C.
Divide and conquer!! :) For example:
8pm - you take your little one into his room, read for 10 minutes and lights out. He is asleep by 8:30.
8:15 - hubby takes 5 YO to quiet spot (your bedroom/a quiet corner of the couch/no TV on/ lights dim). Read for 15-20 minutes. Then it's to his room where the lights are out and little brother is sleeping.
Explain to them what to expect before you do this and and tell them this is the new rule. No exceptions.
A little bit of, "if you behave/listern/follow the rules you can each have 15 extra minutes at the playground" (or whatever) tomorrow will help, too.
Good luck!