K.H.
Something my husband and I do regularly for our girls is to spend alone time with each one individually. This is on a regular schedule, and we give them our undivided attention. We never sacrifice family time for this...we just take a few hours twice a month for each child. Consistant one on one time with you and your husband may help your oldest to feel special and honored as an individual instead of just brother and son. We are also sure to incorporate our expectations into everyday conversation with our kiddos. That we each have an important role in the family and if someone doesn't do their part, then the family doesn't work the right way. I'd stay away from guilting him into the proper behavior, though. This is an easy trap to fall into, but any cooperation he gives you won't be genuine. Be consistant in whatever you do...don't just wing it when it comes up. Good luck