You might email those relatives with a general conversation about quilting and your interest in it. Share how you enjoy doing it and wondered if any of them had ever quilted or other relatives in the past. Try to get some discussion going and the see what their thoughts are on it in general.
You could always ask a relative who knows the person you want to make a quilt for what her tastes are and if they think that is something they would like.
You could also start with a smaller item and see what happens to that...pot holders - wall hanging - something useful.