There are 2 issues here, 1 is your credit score, which will not allow you to qualify. The other is whether there is a specific reason that your mother asked about this? If your parents live in the home and are behind on mortgage payments, you will not be able to "buy" it from them to get a better rate. This is considered a non-arms length transaction, and a bail out of sorts. I can't think of another reason why your mother would want to do this.