Recently my husband and I have began sharing the task of putting our children to bed. They currently share a room, they are both boys 2 1/2 and 5 1/2. When my husband puts them to bed they generally go to sleep easily. When I put them to bed the 2 year old often takes an hour or more to fall asleep and usually ends up waking the 5 year old up several times. Our 5 year old has school and needs his sleep. The 2 year old still naps about 2 hours each day and isn't ready to sleep until the 5 year olds bedtime. We do the same bedtime routine most every night. I get so frustrated and tired because I need my down time each night and feel like I can't always get it.
I would put the school aged child to bed first, and after he falls asleep have a ritual for the younger child to fall asleep, wake the younger child up early with the school aged child.
Dont give in to your 2 year olds demands, if he has learned to go to sleep with dad, he needs to know to do it with mom too....or heck, just let dad do it every night. (pick your battles)