Big Brother Syndrome

One thing that worries me about having a new baby welcomed into our family is this...

I don't want everyone to forget about AJ. God willing my newest angel will be autism free and what does that mean for AJ? My sister said something to me the other day, and I know she was joking but it rubbed me the wrong way. She said that when the new baby comes she is claiming him/her. Now I'm not going to call her a bad aunt because I know she loves AJ very much. My issue is that she has never called me and said "Hey sis, can I have AJ for (insert timeline here) because I want to spend some time with him." or "Hey sis, I'm going to go to (insert place here) and I think AJ would like it, can he come with me?"

I'm scared that if baby #2 is perfectly fine our family will swarm around him/her because they are the typical child they wish AJ would have been. I'm also afraid they will kinda push him aside so they can dote over this perfect child. They all thought I was joking when I told them that if they take #2 they have to take baby #1 as well. But little did they know I was and am very serious about that. I will not allow my children to be treated differently because one has autism and one does not. I will love my children equally and I expect everyone else to love them equally as well.

Are my fears just me being hormonal and overreacting or am I justified?