My son is jealous of the new baby,so what 2 do?

My son Scott Jr is very jealous of the new baby Skyler Foxx and the new kid is not even here yet.He see's all of the new things that are not for him.But he has lots of questions.we've talked scott lots of times.but he's only 4 years old.going on 40 lol .What do we do or what can we say to him.I think he is playing us.so he can get what he wants.