Seeing their kids off to college is a dream many parents share, but co-signing the student loan to get them there can have nightmarish consequences.

These days, many students need help to cover the skyrocketing costs of college. At public four-year schools, costs for the 2015–16 school year rose to $19,548 from the $16,178 price tag five years ago, according to the College Board. Tuition plus room and board at four-year private universities was much, much higher: $43,921 on average.