My mom wants my brother to co-sign a 30 year real estate loan with her

My mom has been homeless for the past year, jumping from hotel to hotel, and my brother has been staying with her, mostly out of obligation and to help her pay for their hotel rooms. It took him awhile to start working after high school, but he is now, and I’m incredibly proud of him. He doesn’t need to live with my mom anymore, he could, with some help, strike out on his own. But I don’t think my mom could manage without assistance of some kind. All of this is worrying enough for me, but my mom has also been trying to get a home loan. She found one (that I’ve looked into: it is legitimate) that requires no down payment, and is stretched out over 30 years of monthly payments. The problem is this: her credit score and income is not enough by itself to attain this loan. But my brother has very fresh credit (no established credit, but no bad credit either), a solid job, and a lot of money saved up. It looks like, if he co-signed this loan, they would both be able to get a house, and pay a mortgage instead of expensive “rent” to a series of hotels. Mom said that he’d be removed as soon as possible from the loan, so it would all be on her, and both of them would be living in this house either way, but I’m still incredibly worried. I wanted to post here and see if my worry is justified, and if so, what should I do?