This is a very difficult question to answer without a great deal of additional information. It may well be that there was illegal or fraudulent conduct involved, which may provide a defense to foreclosure for you.
You need an attorney who is knowledgable in foreclosure defense. The National Association of Consumer Advocates maintains a geographical list of consumer law attorneys all over the US on its web site, www.naca.net
I am not licensed to practice in your state so I cannot answer your questions directly as they are governed by local law. In Florida you would have a claim against your brother in law for deceptive trade practices. As to attending the foreclosure, consult a local attorney. You can usually find a low cost consult with your local county bar association referral service.