You need to explain the matter from initially and in depth as Rajiv Lodha says.
As I said earlier, involve some respectful common members of both families. As you said very little hope, they may not listen then take next step
As Hemant says, take responsibility of medical treatment on your family, which way if medial expense is the issue, can be short out initially.
you can take both steps at the same time in first meeting.
Your foremost priority to get well soon with medical treatment. If you are not healthy, you will not able to fight anywhere. To fightly legally you will need lots of time and money. If you are spending on your medical treatment, you may not wish to spend time, money & take stress for legal matter then finish your medical treatment first. Keep tracking of activities as Hemant says to collect evidences. (Slowely slowely catch the monkey)
When you ready, take legal action. Which will take lots of time so be prepared for that. Meantime, keep lots of patient. Even you fight, they will not take you home or help you anyway right now as you said only 0.1% hope.
You can write to Kiran Bedi for mediation. (I watched some episode of her justice and she helped in such cases)
At worst case, Divorce is the final stage. As Rajoo says file for maintainnce. Law says rights has remedies so will favour you.
