Ed, you may have to wait a bit before you can do much helping on account of your age. But, perhaps you can work on being "cheerful" for your sisters (playing with them, helping them with their homework, being there for them to talk to and trying to keep them from being so afraid). It doesn't sound like adults are taking very good care of you. That's not your fault and not something you can change very easily. Do you and your sisters get enough to eat and have a place to stay so you won't have to move again?

I would try to join a group (boy scouts or a young people's church group, something like that) and get to know some other guys your age and their parents. Maybe you'll meet a friend's father or mother who might have a better idea how to help you. Check out other teachers in your new school, librarians, etc. to see if there's maybe someone who knows your local situation better from an adult perspective and can help.