Maybe he will be. There is no telling. Just don't use any of his blankets for new baby. My brothers ex wife learned that the hard way! My nephew pulled his sister out of the bouncer because she used his blanket for the new baby. It was on carpet and she was fine!
I have always been a little worried about having already having kids and bringing another baby into my family. What I find that works well, and this is my seventh pregnancy, is to always include the older children from the very beginning. Children are very amazing! Talking to them and explaining things in a way they will understand helps! Asking for their help and making them understand that they are not less important than the new baby makes them understand so much better. Giving them responsibility that involves the new baby makes them feel a sense of pride as well as love! Children are awesome and just want to feel important.