Hi dear,
You have written that boy is ill from brain and heart. What do you mean by this? Is he having ailment of brain n heart or you mean he is somewhat mentally challenged.
I personally feel that if the family is greedy n demands dowry then the girl should not accede to their demands. You should try anyhow to contact and talk to your husband. Communication is must. Talk like two educated persons and see where the problem lies. Everything has its solution. But first you both need to talk. Take help of your relatives to help you reach to him.
If you are willing to live with him n he is not ready to take you to his place, then first try to talk to him, secondly, you both can request any senior family member(whom he respects) to do counselling n thirdly, you can file a case for restitution of conjugal rights.
I hope things will get better soon.