Unfortunately some people are just cold a holes and only look out for their own best interests no matter how their actions effect others. I’m sorry that your BIL happens to be one of those people and you are getting caught up in that

I will be crossing my fingers for you that you find a great place where you will be happy and comfortable. Your rent should be income-based, and they won’t leave you with nothing. So, try hard not to worry about that as much as you can for the time being