K.S.
Hi J.,
This sounds like a natural part of having a new baby. The first child is struggling with not getting as much attention. Do you involve the 2 year old with the baby? For example, ask the 2 year old to get a diaper or wipes, or something. It will help him to know that he is included and special. I can also say spanking is NOT the answer. I think you should not EVER do that unless the child is in danger or putting someone else in danger.
In this case, he is trying to show his baby sister love and protection, not hurt her. Even if he does miss being a baby and getting attention children love each other and it is up to us as parents to show them how to love the right way. I do think that until the 2 year old understands that the baby needs her own space, it would be a better idea to seperate them. I would say for your sanity as well as theirs. LOL
One other thought is to get your son a baby to care for. It could be a stuffed animal, or whatever. He can then be like mommy taking care of his baby instead of yours. :)
Blessings to you and your family...
K.S.