No one can say with any certainty what will happen if you get the authorities involved, but I believe you have a moral obligation to act to protect your younger siblings and, in so doing, you will probably help your older brothers and your mother as well. Call the police and explain the situation and they will then call social services and the process will start. In the short term, the younger children will probably be removed from the home while the situation is investigated. The title to the house will probably not be affected by the call to the police and the social services investigation, although that could depend on the extent of and type of criminal activities taking place in the house.
By submitting this question, I suspect that you already know what you should do and I hope you can follow through and contact the authorities. Good luck.