In fact, my dear sister, you will be disobeying Allah if you stay with him. Marriage was made for the comforts of both spouses, not torture.
He is evil, his character is messed up, and he has tortured you both mentally and physically. you even have a right to qisas (because he burned you, you have the right to go to court and do the same to him.
be happy your second elder brother supports you. take his help and go to court and end this daamnd marriage before it's too late this man is a sicko nd he is mentally ill too.