I have the same problem and trying to get my husband to let her know she has to back off, she legit comes home and goes straight for my son and wants to feed him and do all kinds of things and try's to tell me what to do with him.

Well maybe what @cubanese did. You might just have to distance yourself from her.

@momtobetobabyc, I've tried. She just doesn't care

Politely tell her that she's raised her child(ren) and you'd appreciate it if she let you raise yours.