Should she co-sign his loan?

Should she co-sign his loan?

“My brother used to be terrible with money so his credit score is horrendous. He’s trying to buy a house but he needs someone with good credit to co-sign. He makes good money now but I feel anxious because he doesn’t save his money. I want to help but I’m worried if he stopped having money come in that he’d be unable to pay his bills, affecting my credit.”