What should I be doing?Pls advice

Wow.

You can go ahead and elope, but remember, this sounds like a lady who will not rest in peace until she sees you two torn apart. You may be adhesive and stick to him, but he may lose the will power eventually, and YOU will be stuck dealing with a nasty divorce. His mom will easily find someone else for him.

Jeez, I'd stay away from such a drama family if I were you. Remember, SHE raised him. What if he's like her?