Mother in law between husband and wife?

No, he is not helpless. He is perfectly fine and not mentally disabled or incapable of making the right decisions a husband should make. And is it me or is your MIL living with you guys? You need to live separately or you will forever have problems with her. It's very easy to take control of the situation. Either he begins to act like a man or you're gone. Once you have that baby all hell will break loose. TRUST me, you need to leave with your husband or make him build a room out back for her. She needs to be separate there is no other way.