If you weigh that much, you are not the one going to the store and buying food! Whoever is supplying the food is the one who can control the quality and quantity of food. Losing weight is not easy by no means, I have been there and know that it is YOU that needs to make the sacrifice.
Although the family could provide moral support, it is not their responsibility to lose the weight for you. I'm sure that you enabled yourself to get to a considerable weight. Now that you are apparently homebound, your family should be grateful that at least someone is willing to take care of you. I know that exercising is out of the question at this point, but you can start by not sitting in a chair all day long.
A food adiction is not like alcholism......you can live without ever putting a drop of liquor in your mouth but you can not live without putting some food in your mouth!