Serious decisions

So I am in a bit of a dilemma. My little brother was engaged and him and his EX fiance bought a house together. Well, 2 months before the wedding she decided she wasnt ready and left him. He has a great job but his mortgage is $1100 a month plus his other bills he is treading in high water. His bills are $200.00 more a month than his income and that is not including gas to get to and from work. So our littlest brother, who is 19 and a freshman in college at NIC decided to move in and pay $250 a month for rent. Well, they got along till my brother who owns the house got a girlfriend who mooches off of Matt. She is super nice but she is a full time student at NIC as well and she practically lives with Matt. She eats all their food, does her laundry there and showers there too. This all costs Matt more money and Michael, our littlest brother is getting irritated with her being a free loader. So Michael told Matt he was moving out because Melinda was a free loader and he is sick of her eating all their food and basically living there for free. Michael is moving back in with our parents. So, I feel bad for Matt. He is broke and he needs to catch a break. I told him that Caleb and I would move in for $500 a month but that there will be some serious rules! NO PARTIES!!!! Matt it 22 and has parties at his house. If I move in they cant happen. Im not sure if it is a good idea to move in. I want to help him out. When me and Calebs dad broke up I had nothing and he helped me out a lot. I feel like I should return the favor. I mean he is my brother and I dont want him to struggle like I did. But I also hope this doesnt ruin our relationship. I have been really thinking about it and praying about it. Im just not sure if I want to have to move Caleb from the only home he has ever known and also what if I cant handle Melinda being there all the time.Im not the type to hold my tongue. I will tell her where to go if she pisses me off. Ugh..... this is a serious decision!